Some men, thus excited, wax lyrical (7)
I believe the answer is:
enthuse
'wax lyrical' is the definition.
(I've seen this before)
'some men thus excited' is the wordplay.
'some' indicates a hidden word (some of the parts of the word are used).
'ENTHUSE' can be found hidden inside 'men thus excited'.
(Other definitions for enthuse that I've seen before include "Show passionate zeal (about something)" , "Show feeling of eager liking and approval" , "Make keen" , "Show lively interest and keenness" , "Cheer" .)