Seamen’s breaks together (2,5)
I believe the answer is:
en masse
'together' is the definition.
(thesaurus)
'seamen's breaks' is the wordplay.
'breaks' indicates anagramming the letters.
'seamens' is an anagram of 'EN MASSE'.
(Other definitions for en masse that I've seen before include "All together as a group" , "Many as one" , "in concert" , "All together - in France (2.5)" , "In a group U altogether" .)