'Sole' used in pun I queried (6)
I believe the answer is:
Here is my best explanation:
''sole'' is the definition.
('unique' can be a synonym of 'sole')
'in pun i queried' is the subsidiary indication.
'in' indicates the answer is hidden within the clue.
'unique' is hidden within 'pun i queried'.
'used' is the link.
(Other definitions for unique that I've seen before include "The only one of its kind", "Without equal or like", "it's most unusual", "One of a kind", "Singular, not like any other", "Being the only example", "Singular, one of a kind", "Single", "With no equal" and "Individual".)