Sons to become weak in The Spinnaker? (4)
I believe the answer is:
sail
'the spinnaker?' is the definition.
(spinnaker is a kind of sail)
'sons to become weak' is the wordplay.
'sons' becomes 's'.
'to become weak' becomes 'ail' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
's'+'ail'='SAIL'
'in' is the link.
Can you help me to learn more?
(Other definitions for sail that I've seen before include "Spanker, say" , "Travel on water propelled by wind" , "Go by boat" , "Travel by ship" , "Navigate" .)