To do wrong to a good end, seems strange (3)
I believe the answer is:
odd
'strange' is the definition.
(I've seen this before)
'to do wrong to a good end' is the wordplay.
'wrong' is an anagram indicator.
'to a good end' becomes 'd' (I can't justify this - if you can you should give a lot more credence to this answer).
'do' with letters rearranged gives 'od'.
'od'+'d'='ODD'
'seems' acts as a link.
This may not be right. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for odd that I've seen before include "Funny" , "like twenty two [FIFTEEN]? Yes and no!" , "It's certainly not even" , "Unusual, strange" , "Freakish" .)