noun
intuition; sixth sense; gut feeling
Refers to an instinctive, non-rational ability to perceive or judge something correctly. Often used in phrases like 勘がいい (have good intuition) or 勘で動く (act on a hunch).
彼は勘が鋭いから、すぐに嘘を見抜く。
He has sharp intuition, so he quickly sees through lies.
何となく嫌な予感がした。ただの勘だけど。
I had a bad feeling for some reason. It's just a hunch, though.
直感 is a more immediate, flash-like intuition, while 勘 is a broader, experience-based sixth sense or gut feeling.
The kanji 勘 originally relates to investigation or consideration, but the modern meaning of 'intuition' is a semantic extension. The exact historical derivation is uncertain.