Model piece of text shortly disappeared (7)
I believe the answer is:
paragon
'model' is the definition.
(paragon is a kind of model)
'piece of text shortly disappeared' is the wordplay.
'piece of text' becomes 'para' (abbreviation for paragraph).
'shortly' means to remove the last letter.
'disappeared' becomes 'gone' (going is a kind of disappearing).
'gone' with its last letter taken off is 'gon'.
'para'+'gon'='PARAGON'
(Other definitions for paragon that I've seen before include "Perfect diamond" , "An ideal" , "Perfect type" , "Very good example" , "Flawless model" .)