imperil (verb) imperil: cause to be in danger
Sinonime: backward, bottom up, bottom-side-up, confused, disordered, downside-up, haywire, helter-skelter, in chaos, in disarray, jumbled, mixed-up, on head, reversed, tangled, topsy-turvy, upended, wrong way, wrong-side-up
Antonime: right-side-up