去 (qù) — to go (to a place); to go in order to do something (used before another verb)

去 means 'to go' — movement AWAY from the speaker. Use 到 for 'to arrive'. 去 also goes before another verb to mean 'going to do' (我去买).

Two or more meaningful parts placed together so that their meanings combine into a new one.

去 pairs 大, a man, with 口, a mouth or object. The evidence reads this as a man leaving a place, a man opening his mouth, or a cover over an object.