Sci-fi guru having frolic in church (6)
I believe the answer is:
clarke
'sci-fi guru' is the definition.
The definition suggests a singular noun which matches the answer.
'frolic in church' is the wordplay.
'frolic' becomes 'lark' (synonyms).
'in' means one lot of letters goes inside another.
'church' becomes 'CE' (Church of England).
'lark' placed inside 'ce' is 'CLARKE'.
'having' is the link.
Can you help me to learn more?
(Other definitions for clarke that I've seen before include "Arthur C. --, author" , "composer of Trumpet Voluntary" , "Arthur C --, writer" , "Roddy Doyle's Paddy" .)