Dishevelled detective has line on company boss (7)
I believe the answer is:
columbo
'dishevelled detective' is the definition.
Although both the answer and definition are singular nouns, I don't see how they can define each other.
'line on company boss' is the wordplay.
'line' becomes 'l' (used when specifying particular lines from a poem).
'on' says to put letters next to each other.
'company' becomes 'co' (abbreviation).
'boss' becomes 'umbo' (the boss on a shield).
'l' after 'co' is 'col'.
'col'+'umbo'='COLUMBO'
'has' is the link.
Can you help me to learn more?
(Another definition for columbo that I've seen is " TV lieutenant".)