Fictional detective: a married investigator probing swindle (7)
I believe the answer is:
campion
'fictional detective' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'a married investigator probing swindle' is the wordplay.
'married' becomes 'm' (abbreviation, e.g. in genealogy).
'investigator' becomes 'PI' (private investigator).
'probing' is an insertion indicator (probe can mean to poke or prod into).
'swindle' becomes 'con' (con is a kind of swindle).
'a'+'m'+'pi'='ampi'
'ampi' placed inside 'con' is 'CAMPION'.
Can you help me to learn more?
(Other definitions for campion that I've seen before include "Here's one blooming" , "Edmund ---, martyr; Thomas ---, poet/lute composer" , "Wayside flower" , "Wild flower (red, white or bladder)" , "Film director" .)