obviate (en)

(verb) to anticipate and prevent (as a situation) or make unnecessary (as an action)

occidental (en)

(adj) relating to the west

occiput (en)

(noun) the back part of the head or skull

occlusive (en)

(adj) occluding or tending to occlude (stop, close up, obstruct, etc)

odalisque (en)

(noun) a female slave / (noun) a concubine in a harem

Oder-Neisse line (en)

the international border between Germany and Poland; drawn at the Potsdam Conference in the aftermath of WWII

officious (en)

(adjective) kind obliging / (adjective) dutiful / (adjective) volunteering one's services where they are neither asked nor needed; meddlesome / (adjective) informal unofficial

oikos (grk)

household

oneiric (en)

(adjective) of or relating to dreams; dreamy

onomastic (en)

(adjective) of, relating to, or consisting of a name or names

ontic (en)

(adj) relating to entities and the facts about them; relating to real as opposed to phenomenal existence (philosophy)

ontogenetic (en)

(adjective) of, relating to, or appearing in the course of ontogeny (the origination and development of an organism) / (adjective) based on visible morphological characters

ontology (en)

(noun) a branch of metaphysics concerned with the nature and relations of being / (noun) a particular theory about the nature of being or the kinds of things that have existence

operaismo (it)

workerism: a political theory that emphasizes the importance of, or glorifies, the working class

opprobrium (en)

(noun) something that brings disgrace / (noun) public disgrace or ill fame that follows from conduct considered grossly wrong or vicious / (noun) contempt reproach

ordoliberal (en)

the German variant of social liberalism that emphasizes the need for the state to ensure that the free market produces results close to its theoretical potential

ordure (en)

(noun) excrement / (noun) something that is morally degrading

orgone (en)

(noun) a vital energy held to pervade nature and be a factor in health in the theories of Wilhelm Reich

orotund (en)

(adjective) marked by fullness, strength, and clarity of sound; sonorous / (adjective) pompous bombastic

orphic (en)

concerning the ancient Greek poet Orpheus

osculating (en)

(verb) kiss

osiers (en)

(noun) any of various willows (especially Salix viminalis) whose pliable twigs are used for furniture and basketry / (noun) a willow rod used in basketry / (noun) any of several American dogwoods / (noun) red osier / (noun) a common shrubby North American dogwood (Cornus stolonifera syn. C. sericea) with reddish-purple twigs, small white flowers, and globose blue or whitish fruit

ossivorous (en)

bone-eating

ostinato (en)

(noun) a musical figure repeated persistently at the same pitch throughout a composition (from Italian)

otiose (en)

(adjective) producing no useful result; futile / (adjective) being at leisure; idle / (adjective) lacking use or effect; functionless