Tackle husband's old friends (4)
I believe the answer is:
kith
'old friends' is the definition.
('kith' is an old term for one's friends)
'tackle husband's' is the wordplay.
'tackle' becomes 'kit' (both can mean gear or equipment).
'husband' becomes 'h' (abbreviation).
'kit'+'h'='KITH'
(Other definitions for kith that I've seen before include "knowledge" , "Friends (archaic)" , "Friends and neighbours, not family" , "Friends and acquaintances" , "Acquaintance" .)