Striking, effective (8)
I believe the answer is:
dramatic
I believe this is a double definition.
'striking' is the first definition.
(I know that striking can be written as dramatic)
'effective' is the second definition.
(thesaurus)
(Other definitions for dramatic that I've seen before include "Like play" , "relating to plays, etc" , "Sensational, theatrical" , "might be staggering" , "Like theatre" .)