per·cip·i·ent 
(pər-sĭpē-ənt)
(pər-sĭpē-ənt)adj.
Having the power of perceiving, especially perceiving keenly and readily.
n.
One that perceives.
[Latin percipiēns, percipient-, present participle of percipere, to perceive; see PERCEIVE.]
per·cipi·ence, per·cipi·en·cy n.