Pals (5)
'pals' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for friends that I've seen before include "Intimate acquaintances" , "''..., Romans, countrymen, lend me your ears'' (Julius Caesar)" , "Intimates" , "Buddies" , "Pals, comrades" .)
(Other definitions for mates that I've seen before include "conclusive moves on board" , "Naval officers'" , "Pals or spouses" , "Husbands, wives or pals" , "Chums" .)