Whole piece of paper, it nearly flipped over (6)
I believe the answer is:
entire
'whole' is the definition.
(similar in meaning)
'piece of paper it nearly flipped over' is the wordplay.
'piece of' indicates a hidden word.
'flipped over' says the letters should be written backwards.
'eritne' is hidden within 'paper it nearly'.
'eritne' reversed gives 'ENTIRE'.
(Other definitions for entire that I've seen before include "Utter" , "excluding nothing" , "Full, intact" , "Unmitigated" , "Whole - undamaged" .)