Cheap and nasty short containing rum (6)
I believe the answer is:
shoddy
'cheap and nasty' is the definition.
(I've seen this before)
'short containing rum' is the wordplay.
'short' becomes 'shy' (I've seen this in other clues).
'containing' indicates putting letters inside.
'rum' becomes 'odd' (rum can mean strange or dubious).
'shy' enclosing 'odd' is 'SHODDY'.
(Other definitions for shoddy that I've seen before include "Of poor quality or workmanship" , "poor quality fabric" , "inferior cloth" , "Gimcrack" , "clippings in this" .)