Tetchy means easily annoyed — irritable, quick to snap, in the mood where you would rather people just left you alone. It works for people ('Dad's a bit tetchy today'), for what they say ('a tetchy reply'), and for shared situations ('the mood in the room turned tetchy', 'tetchy talks between the two sides'). Two things are worth noticing about how it is really used. First, it describes a passing mood far more than a fixed character; a tetchy person is usually tired, hungry, ill, or fed up, and will be fine tomorrow. Second, it is mild and slightly affectionate — you call your grandfather tetchy, not your boss who screamed at you. It softens the criticism. It is mainly British and mainly written; American writers use it too but less. In everyday Taiwanese classrooms and conversation you will hear grumpy, cranky, or 'in a bad mood' far more often, and testy is its close cousin with almost the same meaning. If a student asks the difference between tetchy and testy: honestly, very little, and even native speakers use them interchangeably. Tetchy leans a touch more towards childish sulkiness, testy a touch more towards sharp adult impatience — but nobody will misunderstand you either way.

脾氣躁、一點小事就不高興的（多半指一時的心情）。像是「今天火氣有點大」「情緒不太好、講話帶刺」。語氣其實偏溫和、帶點無奈的寵溺，說長輩 tetchy 是可以的，說對你大吼大叫的上司就太輕描淡寫了。