Copy and paste from Word into ArcGIS Online item description results in added syntax

Using ArcGIS Online

I am trying to copy and paste a summary description I’ve written in a Word document into the ArcGIS Online item description. For some reason, a long string of syntax gets added after I click save (I think this is the background code to the word document). Is there a way to prevent this from happening? This is a sample of the syntax that is added:
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Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:”Table Normal”; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:””; mso-padding-alt:0mm 5.4pt 0mm 5.4pt; mso-para-margin-top:0mm; mso-para-margin-right:0mm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0mm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:”Calibri”,”sans-serif”; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:”Times New Roman”; mso-bidi-theme-font:minor-bidi;}