Observant (9)
(Other definitions for receptive that I've seen before include "Prepared to listen" , "Open to ideas or change" , "Open to new ideas, interested" , "Open to new things" .)
'observant' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for attentive that I've seen before include "Showing courtesy to another, or alert" , "Alert; observant" , "Heedful, thoughtful" , "Taking notice" , "Dutiful" .)
'observant' is the definition.
(similar in meaning)
This is the entire clue.
(Another definition for perceptive that I've seen is " Aware".)
'observant' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for percipient that I've seen before include "Observant" , "Showing acute insight" .)