Encourage German to enter naked (5)
I believe the answer is:
nudge
'encourage' is the definition.
(thesaurus)
'german to enter naked' is the wordplay.
'german' becomes 'g' (abbreviation).
'to enter' means one lot of letters goes inside another.
'naked' becomes 'nude' (synonyms).
'g' put into 'nude' is 'NUDGE'.
(Other definitions for nudge that I've seen before include "Facility of pinball machine" , "Gently encourage" , "Slight push" , "Gentle poke with elbow" , "Shove" .)