It's easy, thus, to be given short measure (4)
I believe the answer is:
soft
'it's easy' is the definition.
(similar in meaning)
'thus to be given short measure' is the wordplay.
I cannot quite understand how this works, but
'thus' could be 'so' (synonyms) and 'so' is located in the answer.
'measure' could be 'ft' (ft is a kind of measure) and 'ft' is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for soft that I've seen before include "p. (mus.)" , "Native of Riyadh" , "foolish" , "Cushioned" , "Easy to mould or cut" .)