- Organogenetically Adv.
- Organoleptically Adv.
- Organotropically Adv.
- Originally Adv.
- Ornamentally Adv.
- Ornately Adv.
- Ornithologically Adv.
- Orogenetically Adv.
- Orographically Adv.
- Orthodoxically Adv.
- Orthogenetically Adv.
- Orthogonally Adv.
- Orthographically Adv.
- Orthopedically Adv.
- Oscillographically Adv.
- Oscilloscopically Adv.
- Osmotically Adv.
- Osseously Adv.
- Ostensibly Adv.
- Ostensively Adv.
- Ostentatiously Adv.
- Osteologically Adv.
- Osteopathically Adv.
- Otherly Adj. Adv.
- Otherwhere Adv.
- Otherwheres Adv.
- Otherwise Adv. Konj.
- Otherworldly Adj. Adv.
- Otiosely Adv.
- Otologically Adv.
- Out Adj. Adv. Präp. Verb Subst.
- Out-and-out Adj. Adv.
- Out-of-control Adj. Adv.
- Out-of-doors Adv. Subst. Adj.
- Out-of-the-box Adj. Adv.
- Outback Adj. Subst. Adv. Eigenn.
- Outboard Adj. Subst. Adv.
- Outbye Adj. Adv.
- Outdoors Adv. Subst.
- Outlandishly Adv.
- Outrageously Adv.
- Outright Adj. Adv.
- Outside Adj. Adv. Subst. Präp.
- Outspokenly Adv.
- Outstandingly Adv.
- Outward Adj. Adv. Subst.
- Outwardly Adv.
- Outwards Adv. Adj.
- Outwith Präp. Adv.
- Ovally Adv.
- Ovately Adv.
- Over-the-counter Adj. Adv.
- Over-the-top Adj. Adv. Subst.
- Overall Adj. Adv. Subst.
- Overambitiously Adv.
- Overapprehensively Adv.
- Overarm Adj. Adv.
- Overassertively Adv.
- Overattentively Adv.
- Overbearingly Adv.