Idea is negative, getting into trouble (6)
I believe the answer is:
notion
'idea' is the definition.
(I know that notion is a type of idea)
'negative getting into trouble' is the wordplay.
'negative' becomes 'no' (no is a kind of negative).
'getting' means one lot of letters go next to another.
'trouble' is an anagram indicator.
'into' is an anagram of 'tion'.
'no'+'tion'='NOTION'
'is' is the link.
(Other definitions for notion that I've seen before include "desire" , "Vague or whimsical idea" , "Idea or fancy" , "Caprice" , "Whim or fancy" .)