Pressure on a Latin friend (3)
I believe the answer is:
pal
'friend' is the definition.
(pal can mean a friend)
'pressure on a latin' is the wordplay.
'pressure' becomes 'p' (abbreviation).
'on' says to put letters next to each other (in a down clue, letters appear on others).
'latin' becomes 'l'.
'p'+'a'+'l'='PAL'
(Other definitions for pal that I've seen before include "Bud" , "China" , "Buddy, chum" , "Mate, informal friend" , "Friend (colloq.)" .)