What will it do if it catches a fly? (7)
I believe the answer is:
swallow
'a fly?' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'what will it do if it catches' is the wordplay.
I cannot really understand how this works, but
'will' could be 'll' (contracted form, as in 'he'll' - 'he will') and 'll' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for swallow that I've seen before include "put up with" , "Ingest - bird" , "Consume - bird!" , "Bird - gulp down" , "flier" .)