Range.SynonymInfo (Word)

Returns a SynonymInfo object that contains information from the thesaurus on synonyms, antonyms, or related words and expressions for the contents of a range.

Slist = Selection.Range.SynonymInfo.SynonymList(Meaning:=1) 
For i = 1 To UBound(Slist) 
 Msgbox Slist(i) 
Next i