One bar's busy and one's rough (8)
I believe the answer is:
abrasive
'rough' is the definition.
(similar in meaning)
'one bar's busy and one's' is the wordplay.
'one' becomes 'a' (a thing is one thing).
'busy' indicates an anagram.
'and' means one lot of letters go next to another.
'one's' becomes 'ive' ('one has' can mean 'I have').
'bars' with letters rearranged gives 'bras'.
'a'+'bras'+'ive'='ABRASIVE'
(Other definitions for abrasive that I've seen before include "Arabs vie to be harsh or provocative" , "Rough to the touch" , "Harsh in manner, capable of causing anger" , "Pumice, for example" , "Rough and scratchy" .)