Hot line seen in various notes (6)
I believe the answer is:
stolen
'hot' is the definition.
(I've seen this before)
'line seen in various notes' is the wordplay.
'line' becomes 'l'.
'seen in' indicates putting letters inside.
'various' is an anagram indicator.
'notes' is an anagram of 'stoen'.
'l' put inside 'stoen' is 'STOLEN'.
(Other definitions for stolen that I've seen before include "Taken without the owner's consent" , "Purloined in Solent" , "Nicked" , "subject to plagiarism" , "Hot item" .)