Happening to be par for first tee (5)
I believe the answer is:
event
'happening' is the definition.
(I know that happening can be written as event)
'par for first tee' is the wordplay.
'par' becomes 'even' (I've seen this before).
'for' says to put letters next to each other.
'first tee' becomes 't' (1st letter of 'tee').
'even'+'t'='EVENT'
'to be' acts as a link.
(Other definitions for event that I've seen before include "important" , "contest in programme" , "Meeting" , "match" , "riding competition" .)