Suppress, cut off a syllable (5)
I believe the answer is:
elide
I believe this clue is a double definition.
'suppress' is the first definition.
(I've seen this before)
'cut off a syllable' is the second definition.
(I've seen this in another clue)
(Other definitions for elide that I've seen before include "Omit (a vowel etc.)" , "Omit (syllable) in speech" , "Suppress - abridge" , "Join together, merge" , "Abridge, omit part" .)