Say this to men in assembly (7)
I believe the answer is:
mention
'say' is the definition.
(mentioning is a kind of saying)
'to men in assembly' is the wordplay.
'assembly' is an anagram indicator.
'to'+'men'+'in'='tomenin'
'tomenin' is an anagram of 'MENTION'.
'this' is the link.
(Other definitions for mention that I've seen before include "Passing reference" , "Make reference to" , "Briefly refer to (something)" , "state" , "Remark" .)