International legislation keeps any number relative (2-3)
I believe the answer is:
in-law
'relative' is the definition.
(I've seen this before)
'international legislation keeps any number' is the wordplay.
'international' becomes 'i' (abbreviation eg in IMF).
'legislation' becomes 'law' (I've seen this in other clues).
'keeps' is an insertion indicator.
'any number' becomes 'n' (mathematical symbol for an unspecified number).
'i'+'law'='ilaw'
'ilaw' placed around 'n' is 'IN-LAW'.
(Other definitions for in-law that I've seen before include "Relation by marriage" , "Near relative" , "Spouse's relation" , "Relative by marriage" , "Meghan to Harry's family?" .)