Friendly final check before end of day (5)
I believe the answer is:
matey
'friendly' is the definition.
('matey' can be similar in meaning to 'friendly')
'final check before end of day' is the wordplay.
'final check' becomes 'mate' (checkmate, the final check in a game of chess).
'before' is a charade indicator (letters next to each other).
'end of' suggests the final letters.
The last letter of 'day' is 'y'.
'mate'+'y'='MATEY'
(Other definitions for matey that I've seen before include "Pally" , "Pirate's chum (colloq.)" , "Friendly, sociable" , "china" , "Close chum (slang)" .)