Perceived (7)
(Other definitions for noticed that I've seen before include "Clocked" , "regarded" , "Marked" , "Detected" , "Realised" .)
'perceived' is the definition.
(I know that perceived can be written as sensed)
This is the entire clue.
(Other definitions for sensed that I've seen before include "Felt, had mental impression" , "'Felt, perceived (6)'" , "Felt, tasted, etc" , "Became aware through mental perception or intuition" , "Became vaguely aware of (something)" .)