Metal core replacing bung foot in water bug (8)
I believe the answer is:
irritate
'bug' is the definition.
(I've seen this before)
'metal core replacing bung foot in water' is the wordplay.
I cannot really see how this works, but
'metal' could be 'ta' (Ta is an example) and 'ta' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for irritate that I've seen before include "Provoke" , "Nettle and annoy" , "Nark" , "Annoy, bother" , "Anger, annoy" .)