Odd or even excerpts from voluntaries (5)
I believe the answer is:
outre
'odd' is the definition.
(outre means unusual or eccentric)
'even excerpts from voluntaries' is the wordplay.
'even excerpts from' indicates alternate letters (letters in even-numbered positions).
The alternating letters of 'voluntaries' are 'OUTRE'.
'or' acts as a link.
(Other definitions for outre that I've seen before include "Freakish" , "over the top" , "Conspicuously unconventional" , "bizarre style" , "Shockingly unusual" .)