Floral garland certain to be withheld from rest (3)
I believe the answer is:
lei
'floral garland' is the definition.
(I've seen this in another clue)
'certain to be withheld from rest' is the wordplay.
I cannot quite see how this works, but
'from' could be 'e' (I've seen this in other clues) and 'e' is present in the answer.
The remaining letters 'li' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for lei that I've seen before include "Hawaiian necklace of flowers" , "neck decoration" , "show of affection?" , "Hawaiian ring of flowers" , "Band of flowers" .)