Choral piece a tiny bit tense (5)
I believe the answer is:
motet
'choral piece' is the definition.
(I've seen this before)
'a tiny bit tense' is the wordplay.
'a tiny bit' becomes 'mote' (I've seen this in another clue).
'tense' becomes 't' (grammatical abbreviation).
'mote'+'t'='MOTET'
(Other definitions for motet that I've seen before include "Totem (anag) ? anthem" , "Polyphonic choral liturgical piece" , "Short piece of church choral music" , "Short sacred choral piece" , "musical piece" .)