Mean team endlessly in training to come out (7)
I believe the answer is:
emanate
'come out' is the definition.
(thesaurus)
'mean team endlessly in training' is the wordplay.
'endlessly' means to remove the last letter.
'in training' is an anagram indicator (to train can mean to grow something into a shape).
'mean'+'team'='meanteam'
'meanteam' with its final letter removed is 'meantea'.
'meantea' is an anagram of 'EMANATE'.
'to' acts as a link.
(Other definitions for emanate that I've seen before include "Come out (of source)" , "spring" , "Issue forth, from a source" , "Issue or spread out from a source" , "Manatee (anag.)" .)