Remarkable way to communicate (6)
I believe the answer is:
signal
I believe this clue is a double definition.
'remarkable' is the first definition.
(signal can mean striking or noteworthy)
'way to communicate' is the second definition.
(I've seen this before)
(Other definitions for signal that I've seen before include "way to communicate" , "Notable; warning sign" , "Conspicuous" , "Not noise" , "Remarkable - communication" .)