Impressive, noteworthy (8)
I believe the answer is:
striking
This clue is a double definition.
'impressive' is the first definition.
(similar in meaning)
'noteworthy' is the second definition.
(thesaurus)
(Other definitions for striking that I've seen before include "stopping work" , "Prominent" , "Signal" , "Noticeable" , "Conspicuous" .)