Plain-clothes cops arresting happy lover-boy (5)

I believe the answer is:

cupid

I'm a little stuck... Click here to teach me more about this clue!

'boy' is the definition.
(I have seen 'naked boy' mean 'cupid' so perhaps 'boy' could also mean 'cupid')

I don't understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for cupid that I've seen before include "Cherubic symbol for love" , "One killed for religion" , "Tiny archer as Roman god of love" , "Armed boy" , "heathen god" .)

I've seen this clue in The Sun and the Financial Times.

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