Maybe it isn't bad? (5)
I believe the answer is:
taint
'maybe it isn't bad?' is the definition.
I can't judge whether this definition defines the answer.
'it isn't bad?' is the wordplay.
'it' becomes ''t' (abbreviation. e.g. in 'tis).
'isn't bad?' becomes 'ain't' (I've seen this in another clue).
't'+'aint'='TAINT'
Can you help me to learn more?
(Other definitions for taint that I've seen before include "Contaminate, pollute" , "Evidence of pollution" , "Adulterate" , "Sully, stain" , "Defect - contamination" .)