Glass initially embedded in bare elbow (5)
I believe the answer is:
nudge
'elbow' is the definition.
(I know that elbow is a kind of nudge)
'glass initially embedded in bare' is the wordplay.
'initially' indicates taking the first letters.
'embedded in' is an insertion indicator (I've seen this in other clues).
'bare' becomes 'nude' (synonyms).
The first letter of 'glass' is 'g'.
'g' put within 'nude' is 'NUDGE'.
(Other definitions for nudge that I've seen before include "Light touch or push" , "A gentle reminder?" , "Dig with elbow" , "Prod gently with elbow" , "Slight push" .)