Terpsichorean cared about entertaining knight (6)
I believe the answer is:
dancer
'terpsichorean' is the definition.
(I've seen this before)
'cared about entertaining knight' is the wordplay.
'about' is an anagram indicator.
'entertaining' means one lot of letters goes inside another (inviting in, as for dinner).
'knight' becomes 'N' (chess abbreviation).
'cared' anagrammed gives 'dacer'.
'dacer' placed around 'n' is 'DANCER'.
(Other definitions for dancer that I've seen before include "One moves to music" , "See 25" , "Eg, ballerina" , "behind Rudolph" , "Fred Astaire, say" .)