Topless dance after separation is out of sentimentality (8)
I believe the answer is:
schmaltz
'sentimentality' is the definition.
(schmaltz is a kind of sentimentality)
I cannot understand how the remainder of the clue works.
(Other definitions for schmaltz that I've seen before include "Sickly sentimentality" , "mush" , "Jewish word meaning sugary sentimentality - has just one vowel" , "mawkishness" , "Excessive sentimentality in art or music" .)