Having seen roaming about, ran out to catch (7)

I believe the answer is:

ensnare

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

'to catch' is the definition.
(ensnaring is a kind of catching)

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

(Other definitions for ensnare that I've seen before include "Ecstatic expression of feeling" , "Ambush" , "Catch as if in a trap or net" , "Capture, trap" .)

I've seen this clue in the Evening Standard.

Want a hint initially instead of a full solution? Install my app