Because the hiragana ends with an う sound, you know this word is a verb. The kanji itself means slice and the verb vocab version means to cut down or to slice off or to lop off. This word mainly refers to cutting people with a sword, if you haven't figured it out yet.
The reading is the same as 切る, which means "to cut." Similar meaning, same reading.
The samurai told me he would cut off my tongue if I couldn’t say the tongue twister properly.