Central digit poking bare elbow (5)
I believe the answer is:
nudge
'elbow' is the definition.
(I know that elbow is a more specific form of the action nudge)
'central digit poking bare' is the wordplay.
'central' indicates the central letters.
'poking' is an insertion indicator (poke can mean to create a hole in).
'bare' becomes 'nude' (synonyms).
The middle of 'digit' is 'g'.
'g' put inside 'nude' is 'NUDGE'.
(Other definitions for nudge that I've seen before include "Push gently" , "Gentle push" , "Gentle encouragement" , "---. ---, wink, wink (Monty Python)" , "Facility of pinball machine" .)