having or showing an ability to notice and understand things clearly : mentally
sharp or clever. Source: Merriam-Webster's Learner's
Someone who is
Having or showing shrewdness and discernment, especially with respect to one's own concerns. See Synonyms at shrewd.
having or showing an ability to accurately assess situati...
very clever and quick at seeing what to do in a particular situation, especially how
to get an advantage synonym shrewd an