Strangely amusing nobleman lifted line (5)
I believe the answer is:
droll
'strangely amusing' is the definition.
(I've seen this before)
'nobleman lifted line' is the wordplay.
'nobleman' becomes 'lord' ('lord' can be a synonym of 'nobleman').
'lifted' says the letters should be written backwards (going up in down clue).
'line' becomes 'l'.
'lord' back-to-front is 'drol'.
'drol'+'l'='DROLL'
(Other definitions for droll that I've seen before include "Clownish" , "Drily amusing" , "Dry" , "rum" , "Oddly amusing or comical" .)