Prune tips of azalea bush on hilltop (7)
I believe the answer is:
abridge
'prune' is the definition.
(thesaurus)
'tips of azalea bush on hilltop' is the wordplay.
'tips of' says to take the initial letters (I've seen 'tip of' mean this).
'on' means one lot of letters go next to another.
'hilltop' becomes 'ridge' (I've seen this before).
The first letters of 'azalea bush' is 'ab'.
'ab'+'ridge'='ABRIDGE'
(Other definitions for abridge that I've seen before include "Crop" , "(US) cattle-pen" , "Shorten (a literary work)" , "Tighten up" , "Shorten written work" .)