Snitty is the adjective for someone in a snit: annoyed about something small, and letting it leak into how they talk to you. It covers both halves at once — the mood itself (he's being snitty today) and the behaviour it produces (a snitty email, a snitty little comment about the deadline). Like snit, the judgement is built in: calling a remark snitty says you find the annoyance out of proportion, and slightly childish. It is informal, mostly American, and it turns up a lot in offices and in politics reporting, where a snitty reply is one that is technically polite but clearly sulking underneath. It sits very close to snippy, and in everyday use many speakers treat them as the same. If you want the fine difference: snippy points at the sharp short way the words come out, while snitty points back at the sulky mood behind them. Both are mild. Neither is something you would write in a formal report — you would say curt or unhelpful there instead.

鬧彆扭的、沒好氣的、帶著情緒的。指人在為小事賭氣，而且那個情緒滲進了講話或寫信的口氣裡（a snitty email 就是「一封語氣很不爽的信」）。偏美式口語，語氣不重但帶貶意。