Different parent blowing top (5)
I believe the answer is:
other
'different' is the definition.
(similar in meaning)
'parent blowing top' is the wordplay.
'parent' becomes 'mother' (type of parent).
'blowing top' means to remove the first letter.
'mother' with its initial letter taken away is 'OTHER'.
(Other definitions for other that I've seen before include "Different (from those mentioned)" , "Different, not the same one or this one" , "else!" , "Alternative of two" , "Very unusual" .)