What is worse than "mediocre"?

subpar:

adjective

below an average level.

If you want to say something is objectively below average, this would be an adequate word. I would say it's less subjective than "bad."

"The roads were in subpar condition." (the roads were of below average condition but not necessarily bad in absolute terms)

substandard

adjective

below the usual or required standard.

"The roads were in substandard condition."

You could consider using substandard which is broadly used to mean:

Below the usual or required standard: 'In the country's capital city, Santo Domingo, much of the housing is substandard and the quality of the water is poor.'

[Oxford Online Dictionary]

Actual usage:

In a damning report released late last week, it emerged that more than one third of roads in the Highlands are of substandard condition. Not only that but roads in the north are deteriorating faster than virtually every other part of Scotland.

[Roadtraffic.com]

In a professional setting, you'd expect to see

Unsatisfactory adj - not good enough
(OED)

Shoddy, unsatisfactory, substandard, abysmal, crummy, third-rate

"The condition of the road was shoddy."

It is not exactly what you asked, and I do not know the full context, but it sounds like a good example of where one could use showing language instead of telling. Again, I know you did not ask that, but I offer it as you said what could be said.

I want to use this in my prose in a context as follows - "The condition of roads was "worse than mediocre" - what can be used here?

"Unlike the nice, straight Roman roads in the city, these "roads" felt like they were adopted by the local carnival, every mile engineered by carnies from the DOT to test vehicle shock absorbers. Each mile had its own unique gravel pockets full of steamy, puddled water. The car bounced and squeaked, the hood floating or the floorpan scraping, and the seat belt buckle tightened against the gut, like sitting in shrunken jeans on a rusty old Tilt-O-Whirl."

Or, just "roads" (in quotes) as in so-called roads.

Or, maybe this is a better answer for the writing Stack Exchange.

I have always considered "mediocre" to be between "good" and "bad," and if you wish to expand the number of descriptors then medi should be based firmly in the center according to the Latin roots; using game definition gradients in my opinion is a poor basis. I understand writers have the desire to vary the words used (a very English problem), but game developers have a different agenda which leads to lack of balance around a central term.

Just to add a different perspective to the "subpar, substandard" discussion;

a) "par" is less of an average more of an expected result, golf par for example is the expected score based on a specific level of golfer, which oddly enough make the best golfers in the world subpar. This has always amused me anyway :)

b) "substandard" again, standards are usually much higher than average leading us to minimum standards as a common 20th century term. I personally think that substandard should only be used where standards are actually involved (road quality would potentially work here).

Something that was briefly touched on was standards in a given region. Not mentioned was the actual subject; that is, discussing roads. If you are thinking an Englishman using a road in some third world where they would be happy to have an actual road surface in most areas, then the subjective view becomes important.

The next step below mediocre, that I can think of, is passable.

passable 1. just good enough to be acceptable; satisfactory: he spoke passable English.

This directly contrasts with the other suggestions such as subpar, substandard, poor, and unsatisfactory, which suggest uselessness. Passable describes something which probably will get the job done.

For roads in particular, this word has a second meaning which fits your question perfectly.

passable 2. (of a route or road) clear of obstacles and able to be traveled along or on: the road was passable with care.

Mediocre does not necessarily mean bad, its meaning is pretty close to ordinary, not special.

E.G.:

Dude, your work in the last project was mediocre

Whereas in Anglish:

Dude, your work in the last project was meh...

I think saying "worse than mediocre" as is, is pretty good.

The condition of the roads in that area were worse than mediocre. Some have said they were pitiful while others have argued they were pathetic. Either way, it is safe to say the roads were not very good.

Sounds kind of Douglas Adamish though.

I want to use this in my prose in a context as follows - "The condition of roads was "worse than mediocre" - what can be used here?

The word you are looking for is poor.

You can't do the job with only one word. You need to add at least a clause, for example:

"the condition of the roads was poor because they had not been paved, but only patched, for the past 15 years."

I write as a connoisseur of roads on the poorish end of the spectrum, from the fair road I live on (winding, narrow, in need of repaving, no shoulders and charming) to some dreadful 4WD roads in Colorado (barely passable by a large SUV with high clearance.)

Mediocre is not a word used to describe roads. (A performance can be mediocre.) For roads, in the sequence quoted by user Lawrence, skip mediocre and go from fair to poor. (If you are in New Hampshire, "middlin'" can be used for anything.)

Abysmal, Awful, Bad, Poor, Mediocre, Fair, Good, Great, Excellent, Amazing, Phenomenal

A word about the upper end of the sequence. A road can be good or excellent, but great sounds odd, applied to a road. As for amazing or phenomenal applied to a road -- you'd sound like a hick seeing a highway for the first time. (Great, amazing or phenomenal can be used to describe a performance.)

I'm not going to get far into the opinion-based argument, except to say that my fair road might be a good road by the standards of someone who lives several miles up a dirt road. But most people will know pretty much what you mean by a poor road -- sort of a 15 mph road.

As for passable or impassable, applied to a road: it depends on what you are driving and how well you drive.

I agree with the descriptive scales above. However, when the roads I am negotiating are not acceptable (worse than mediocre, just passable, average) I've been partial to "disreputable condition of roads", also dilapidated and shoddy. These are not on a logical +/- spectrum, but somehow transcends those, and conveys worse than mediocre, yet not unpassable.

The word you are looking for is "abominable"

Consider the following statement,"Performance of our team in yesterday's match is abominable".

Disappointing.

Given the months of construction delays, the condition of the road was disappointing.

A thing cannot be good or bad or high or low without some standard against which it should be judged. Disappointing tells us that the road was not at the quality level that the speaker expected.

While driving on a gravel road would not be my preference, I would not be disappointed if I had to drive on one in the country. I would be disappointed if an interstate was as busted up as a gravel road.

Context.

How about "mediocre at best"? .

Downright mediocre! Where 'downright' accentuates the mediocre. Downright is defined as: to an extreme degree; thoroughly, i.e."he was downright rude". However, I think this word has greater usage in America rather than in the UK.

Source: Google Dictionary