Teach wrongly to swindle (5)
I believe the answer is:
cheat
'to swindle' is the definition.
(synonyms)
'teach wrongly' is the wordplay.
'wrongly' indicates an anagram.
'teach' with letters rearranged gives 'CHEAT'.
(Other definitions for cheat that I've seen before include "Fool" , "One dealing dishonestly" , "Act unfairly (in game)" , "22 [FRAUDSTER]" , "Fraud" .)