noun
sweat; perspiration
Refers to the liquid produced by the body when hot or nervous. Common in everyday speech.
運動したら汗をかいた。
I sweated after exercising.
緊張して手に汗をかいた。
My hands got sweaty from nervousness.
noun
Used for moisture that appears on surfaces, such as condensation on a cold glass. Less common than sense 1.
冷たい飲み物のコップに汗がついている。
There is condensation on the glass of cold drink.
interjection
Internet slang interjection expressing embarrassment, awkwardness, or mild shock, often written as （汗）. Equivalent to a sweatdrop emoticon.
また遅刻しちゃった（汗）
I'm late again... (sweatdrop)
Native Japanese word. The kanji 汗 is a phono-semantic compound: the left side 氵 (water) and the right side 干 (dry) suggest the idea of moisture that dries.