Exclamation of love for a companion (3)
I believe the answer is:
och
'exclamation' is the definition.
(I have seen 'Scots exclamation ' mean 'och' so perhaps 'exclamation' could also mean 'och')
'love for a companion' is the wordplay.
'love for' becomes 'o' (I've seen this in other clues).
'a companion' becomes 'ch' (I've seen this in other clues).
'o'+'ch'='OCH'
'of' acts as a link.
(Other definitions for och that I've seen before include "Scots exclamation" , "Jock's expression" , "Scots expression of impatience" , "Scottish exclamation" , "Scotsman may cry" .)