Scrooge-like, I'm backing some losers (5)
I believe the answer is:
miser
'scrooge' is the definition.
(Dickens' Ebenezer Scrooge is a miser)
'i'm backing some losers' is the wordplay.
'backing' says the letters should be written in reverse.
'some losers' becomes 'ser' (I can't justify this - if you can you should give a lot more credence to this answer).
'im' in reverse letter order is 'mi'.
'mi'+'ser'='MISER'
'like' acts as a link.
Can you help me to learn more?
(Other definitions for miser that I've seen before include "Tight-fisted person" , "hunks" , "Money-grubber" , "One giving little" , "One hoarding wealth" .)