Prince quick to invest bishop (6)
I believe the answer is:
albert
'prince' is the definition.
(Prince Albert, husband of Queen Victoria)
'quick to invest bishop' is the wordplay.
'quick' becomes 'alert' (I've seen this before).
'to invest' means one lot of letters goes inside another (back).
'bishop' becomes 'B' (abbreviation for bishop in chess).
'alert' enclosing 'b' is 'ALBERT'.
(Other definitions for albert that I've seen before include "Victim of lion" , "Queen Victoria's consort or familiar ex-Taoiseach" , "London bridge, Memorial" , "M [MUSEUM] with 18 [VICTORIA]" , "- Square, Walford (EastEnders)" .)