A short indication of approval heard for puzzle (8)
I believe the answer is:
acrostic
'puzzle' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
(Other definitions for acrostic that I've seen before include "Puzzle involving a hidden message" , "Poem with word(s) reading downwards" , "Socratic sort of word puzzle" , "Poem where first letters of lines spell a word" , "Puzzle involving leading characters" .)