Lent made one lad go mad (6)
I believe the answer is:
loaned
'lent' is the definition.
('loan' can be a synonym of 'lend')
'one lad go mad' is the wordplay.
'go mad' is an anagram indicator (I've seen 'goes mad' mean this).
'one'+'lad'='onelad'
'onelad' anagrammed gives 'LOANED'.
'made' is the link.
(Another definition for loaned that I've seen is " Gave temporarily - want it back".)
I've seen this clue in The Daily Express.
Want a hint initially instead of a full solution?
Install my app