1) to entertain together
2) to feast sumptuously with
Part of Speech: verb
From G4862 and a derivative of a presumed compound of G2095 and a derivative of G2192 (meaning to be in good condition, that is, [by implication] to fare well, or feast); to entertain sumptuously in company with, that is, (middle or passive voice) to revel together: - feast with.
These two sites give similar information, with the definition from several dictionaries and statistics on the use of the word.
Perseus Digital Library
University of Chicago's Logion lexicon
Thayer's dictionary plus other information.
From this site's dictionary (in Italian)
Click on the first column to search for that word as a form of the root συνευωχέομαι; click on the second column to search for that grammatical form of the root συνευωχέομαι; click on the third column to search for that word and grammatical form; click on the total to search for the root συνευωχέομαι.