| keen(adjective, understanding, sharp, fine, smart) |
| kept posted(expression, adjective, familiar, knowledgeable, witting) |
| know-how(adjective, alert, familiar, wise, knowledgeable) |
| know all the answers(expression, adjective, idiom, careful, knowledgeable) |
| know ins and outs(expression, adjective, idiom, careful, knowledgeable) |
| latched on(expression, adjective, alert, familiar, wise) |
| learned(adjective, smooth, reasonable, smart, rational) |
| like-minded(adjective, cool, friendly, agreeable, down) |
| nervous(adjective, understanding, keen, fine, sensible) |
| no stranger to(expression, adjective, idiom, familiar, knowledgeable) |
| observative(adjective, careful, knowledgeable, cautious, aware) |
| observing(adjective, understanding, careful, knowledgeable, cautious) |
| old(adjective, smart, practical, expert, skilled) |
| on same wavelength(expression, adjective, idiom, cool, friendly) |
| on the ball(expression, adjective, idiom, smooth, smart) |
| on the job(expression, adjective, idiom, careful, knowledgeable) |
| on top of(expression, adjective, idiom, knowledgeable, aware) |
| open(adjective, friendly, agreeable, amenable, approving) |
| open-minded(adjective, reasonable, friendly, agreeable, rational) |
| oversensitive(adjective, understanding, keen, fine, sensible) |