Confident getting on with bishop (4)
I believe the answer is:
bold
'confident' is the definition.
(similar in meaning)
'getting on with bishop' is the wordplay.
'getting on' becomes 'old' ('getting on a bit' means 'old').
'with' says to put letters next to each other.
'bishop' becomes 'B' (chess abbreviation).
'old' after 'b' is 'BOLD'.
(Other definitions for bold that I've seen before include "Daring, courageous" , "Confidently courageous" , "No chicken" , "Conspicuous" , "Like heavy type" .)