Unmarried mum finds alternative (5)
I believe the answer is:
other
'alternative' is the definition.
(I've seen this in another clue)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for other that I've seen before include "Alternative of two" , "Very unusual" , "else!" , "Remaining" , "Different, alternative" .)