Let son somehow become hot (6)
I believe the answer is:
stolen
'hot' is the definition.
(eg stolen goods are 'hot')
'let son somehow' is the wordplay.
'somehow' is an anagram indicator.
'let'+'son'='letson'
'letson' anagrammed gives 'STOLEN'.
'become' acts as a link.
(Other definitions for stolen that I've seen before include "Lifted" , "Taken without right" , "Pinched" , "Illegally taken" , "Nicked" .)