Clown Launcelot covering two bachelors in slime (5)
I believe the answer is:
gobbo
'clown launcelot' is the definition.
(Launcelot Gobbo from The Merchant of Venice)
'covering two bachelors in slime' is the wordplay.
'two bachelors' means two substitutions for 'bachelor'.
'covering' is an insertion indicator.
'bachelor' becomes 'B' (abbreviation e.g. BA=Bachelor of Arts).
'bachelor' becomes 'B' (abbreviation e.g. BA=Bachelor of Arts).
'in' is an insertion indicator.
'slime' becomes 'goo' (synonyms).
'b' put into 'goo' is 'gobo'.
'b' put inside 'gobo' is 'GOBBO'.
(Other definitions for gobbo that I've seen before include "Launcelot _____, Shylock's servant" , "Lancelot -, servant(Merchant of Venice)" , "Shylock's servant (M. of V.)" , "Shylock's man" .)