Dainty foxtrot involved in line dancing (5)
I believe the answer is:
Here is my best explanation:
'dainty' is the definition.
'foxtrot involved in line dancing' is the wordplay.
'foxtrot' becomes 'f' (phonetic alphabet: alpha, bravo, charlie etc.).
'involved in' means one lot of letters goes inside another.
'dancing' indicates an anagram.
'line' with letters rearranged gives 'elin'.
'f' inserted inside 'elin' is 'ELFIN'.
(Other definitions for elfin that I've seen before include "Small and fragile", "Like a little fairy", "Little, charming and naughty", "Like a mischievous fairy", "Small, delicate and charming", "puckish", "small and mischievous", "Slight", "Small and delicate like fairy" and "Resembling one of the little people".)