Curiosity may make one tarry (6)
I believe the answer is:
rarity
'curiosity' is the definition.
('rarity' can be a synonym of 'curiosity')
'make one tarry' is the wordplay.
'make' is an anagram indicator.
'one' becomes 'i' (Roman numeral).
'i'+'tarry'='itarry'
'itarry' anagrammed gives 'RARITY'.
'may' is the link.
(Other definitions for rarity that I've seen before include "Uncommon object" , "Unusual thing" , "Curio (1)" , "Unusual item" , "could be something of value" .)