歯医者

How it works

に (to) marks 歯医者(はいしゃ) (the dentist) as the destination. The verb 行く(いく) (go) becomes negative 行かない(いかない) (not go), and the trailing と (if/then) sets up an unspoken consequence: "if I don't go (something bad)…". Leaving the rest off is exactly how Japanese says "I really have to go" — the obligation hangs in the air.