Longing to get first hole in one (4)
I believe the answer is:
ache
'longing' is the definition.
(thesaurus)
'first hole in one' is the wordplay.
'first' says to take the initial letters.
'in' is an insertion indicator.
'one' becomes 'ace' ('ace' can be a synonym of 'one'**).
The initial letter of 'hole' is 'h'.
'h' placed within 'ace' is 'ACHE'.
'to get' is the link.
(Other definitions for ache that I've seen before include "Persistent dull pain" , "Cause pain" , "Shakespearean character" , "Longing" , "Feel pain" .)