One indicates detective employed by Spooner? (8)
I believe the answer is:
dipstick
'one' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'detective employed by spooner?' is the wordplay.
I cannot quite see how this works, but
'detective' could be 'di' (Detective Inspector abbreviation) and 'di' is present in the answer.
This explanation may well be incorrect...
'indicates' acts as a link.
Can you help me to learn more?
(Other definitions for dipstick that I've seen before include "Rod for measuring depth of liquid contents" , "Engine oil measuring device" , "help to motorist" , "one concealed under bonnet?" , "shower of liquid" .)