Push dune buggy, essentially getting knackered (5)
I believe the answer is:
nudge
'push' is the definition.
(nudging is a kind of pushing)
'dune buggy essentially getting knackered' is the wordplay.
'essentially' says to take the centre.
'getting' means one lot of letters go next to another.
'knackered' indicates an anagram.
The middle letter of 'buggy' is 'g'.
'dune'+'g'='duneg'
'duneg' anagrammed gives 'NUDGE'.
(Other definitions for nudge that I've seen before include "Encouraging prompt" , "Gentle push" , "Poke gently with elbow" , "Gentle encouragement" , "Gently encourage" .)