The stomach for a strike around the middle of May (6)
I believe the answer is:
paunch
'the stomach' is the definition.
(thesaurus)
'a strike around the middle of may' is the wordplay.
'a strike' becomes 'punch' (I've seen this before).
'around' is an insertion indicator.
'the middle of may' becomes 'a' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'punch' going around 'a' is 'PAUNCH'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for paunch that I've seen before include "Protuberant stomach" , "Spare tyre" , "Fat belly" , "Large stomach or belly" , "Protuberant belly" .)