Also restriction involving small digit (7)
I believe the answer is:
tootsie
'digit' is the definition.
(I've seen this before)
'also restriction involving small' is the wordplay.
'also' becomes 'too' (synonyms).
'restriction' becomes 'tie' ().
'involving' indicates putting letters inside.
'small' becomes 's' (abbreviation - e.g. clothes size).
'tie' placed around 's' is 'tsie'.
'too'+'tsie'='TOOTSIE'
(Other definitions for tootsie that I've seen before include "Part of foot" , "pretty girl" , "digit" , "Foot or toe (childish)" , "Foot (jocular)" .)