Initially old puzzles appear quite unusual, even cryptic (6)
I believe the answer is:
opaque
'cryptic' is the definition.
(thesaurus)
'initially old puzzles appear quite unusual even' is the wordplay.
'initially' says to take the initial letters.
The first letters of 'old puzzles appear quite unusual even' is 'OPAQUE'.
(Other definitions for opaque that I've seen before include "Non-translucent" , "Dark" , "Obscure" , "Not transparent or clear" , "Nebulous, unclear" .)