“Cheapjack” has a strange cast all round (6)
I believe the answer is:
shoddy
'cheapjack' is the definition.
('shoddy' can be a synonym of 'cheapjack')
'a strange cast all round' is the wordplay.
'a strange' becomes 'odd' (I've seen this before).
'cast' becomes 'shy' (I've seen this before).
'all round' is an insertion indicator.
'odd' placed within 'shy' is 'SHODDY'.
'has' is the link.
(Other definitions for shoddy that I've seen before include "Cheap and poorly made" , "Of inferior workmanship" , "bits of waste material" , "poor quality fabric" , "Of poor quality or workmanship" .)