Friends hot on equipment? (4)
I believe the answer is:
kith
'friends' is the definition.
(I've seen this before)
'hot on equipment?' is the wordplay.
'hot' becomes 'h'.
'on' says to put letters next to each other.
'equipment?' becomes 'kit' (kit is a kind of equipment**).
'h' put after 'kit' is 'KITH'.
(Other definitions for kith that I've seen before include "Acquaintance" , "Friends (archaic)" , "knowledge" , "'... and kin, friends and relations (4)'" , "Friends and neighbours, not family" .)