| Oaf | n | Girlopp, Hylden |
| Oafish | adj | Rouse-About |
| Oak apple | n | Shick-Shack |
| Oak Apple Day | n | Oaken Bough Day |
| Oak blossom | n | Drale, Thrail, Trail |
| Oak sapling | n | Flittern |
| Oak, barked | n | Randle |
| Oatcake | n | Bannock |
| Oat-chaff | n | Oaves |
| Oath | n | Woth |
| Oath, coroner's | n | Cornoral-Oath |
| Oatmeal | n | Cutlings |
| Oats, awn and head of | n | Jag |
| Oats, ear of | n | Haw |
| Oats, wild | n | Erwuts |
| Obese | adj | Bausy, Big as a Dorchester Butt, Gorry |
| Obfuscated | adj | Obfusticated |
| Object, large | n | Quilter |
| Obliquely | adv | Scantways |
| Obscene talker | n | Smut |
| Obstacle in river | n | Stower |
| Obstinate | adj | Thwartover |
| Occasion | n | Casion |
| Occassionally | adv | Otherwhiles |
| Ochre, red | n | Raddle |
| Odd | adj | Comical |
| Odd quantity of grain | n | Cotchel |
| Oddest | adj | Onliest |
| Odour | n | Snitch |
| Of sheep, covered in pellets of clay after feeding in a turnip field | adj | Bewattled |
| Offal | n | Fry, Hange, Haslet, Purtenance, Race |
| Officer of the New Forest | n | Groom-Keeper |
| Off-Kilter | adj | Cam |
| Off-Licence | n | Tiddlywink |
| Often | adv | Oft, Oten |
| Oily | adj | Dubby |
| Old age | n | Oldness |
| Old man | n | Boy, Gatfer |
| Omen | n | Warning |
| Omnibus | n | Omligus |
| On fire | adv | Afire |
| On foot | adj | Walker's Bus |
| On its side (of tossed coin) | n | N-Adgers |
| On purpose | adv | A-Purpose |
| On the ground | adj | Aground |
| On the shelf (of unmarried person) | adj | Shelfy |
| On this side | prep | Behither |
| On top | prep | Atop |
| Once up and down the land (in ploughing) | adv | Brenth |
| One of the strata of Purbeck beds | n | Aish |
| One who hires quarrymen | n | Bargain-letter |
| One who rakes up litter behind a wagon | n | Raker |
| One who rides too far forward in hunting | n | Thruster |
| Onion | n | Cribble, Cullack, Gibble, Ire |
| Only | adv | Enny |
| Onrush | n | Haily |
| Oolite, bed of | n | Gingerbread-stone |
| Ooze | v | Mize, Pease |
| Open (eyes or ears) | v | Unbutton |
| Open space near town wall | n | Forbury |
| Opening | n | Ope |
| Opening in garment | n | Vent |
| Opinion | n | Pinion, Verdict |
| Opinionated | adj | Penny-Headed, Piniated |
| Opposite (1) | adv | Enunty |
| Opposite (2) | adj | Upazet |
| Or more | prep | Anent |
| Orchard Grass | n | Orchis Grass |
| Orchid | n | Gamfergreygle |
| Orchis | n | Orchey |
| Order around | v | Mander |
| Ore, loose | n | Shoad |
| Ornamentation on thatched roof | n | Heckle |
| Ornaments | n | Joneys |
| Oscillate | v | Log |
| Osier | n | Persh |
| Osier-Bed | n | Dings, Osier-Holt |
| Osprey | n | Mullet-Hawk |
| Othello (game), primitive version of | n | Marnull |
| Other | pron | Worther |
| Otherwise | adv | Else, Otherous, Otherways, Wothering |
| Our | pron | Us's, We's |
| Ourselves | pron | Ussels |
| Oust | v | Out |
| Out of doors | adv | Abroady |
| Out of place | adj | Tanterboming |
| Out of sorts | adj | All-Overish |
| Outbuildings | n | Courtledge |
| Outburst | n | Feag |
| Outcry | n | Peal |
| Outer edge of gable | n | Barge |
| Outhouse | n | Skeeling |
| Outsider | n | Kimberlin |
| Oven cleaner | n | Maaker, Mawk. Scovel |
| Oven door, wooden | n | Stopper |
| Over 70 years old (of person) | n | On Trespass |
| Overall | n | Wrapper |
| Overbearing | adj | Mannish |
| Overcast | adj | Howder |
| Overcome | v | Quank |
| Overfeed | v | Glut |
| Overfeed (animal) | v | Par |
| Overfill | v | Druck |
| Overgrown | adj | Lavish, Rambling |
| Overhead | adv | Aboon, Ahead |
| Over-nice | adj | Frinnishy |
| Overripe (of cereals) | adj | Rammely |
| Over-ripe (of fruit) | adj | Mawksy |
| Over-ripe (of pears) | adj | Douty |
| Oversee | v | Overgo |
| Overseer | n | Seer |
| Overstuffed | adj | Frodg |
| Over-sweet | adj | Mawky |
| Overtake | v | Overcatch |
| Overthrow | v | Overdrow |
| Overturn | v | Whelm |
| Overturn | v | Whelve |
| Overturn a bucket | v | Heel |
| Owing to | prep | Along Of/On/With |
| Owl | n | Hooter, Josey, Wink-A-Pussy |
| Owlet | n | Howlet |
| Own | adj | Nown |
| Ox | n | Bummick, Neat |
| Ox, young | n | Steart |
| Ox-eye daisy | n | Dun-Daisy, Maudlin |
| Oxlip | n | Pug-In-A-Primmel |
| Oystercatcher (bird) | n | Shalder |
The Society for Wessex Past, Present and Future