There could be a catch in it, of course (3)
I believe the answer is:
net
'there could be a catch' is the definition.
I can't tell whether this defines the answer.
'it of course' is the wordplay.
I cannot quite see how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
'course' could be 'ne' and 'ne' is located in the answer.
No letters remain.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for net that I've seen before include "Ultimate" , "Overall; mesh" , "land" , "Mesh; entrap" , "Tennis equipment" .)