| obscure |
weakly or poorly illuminated. [6 definitions] |
| obscurity |
the state or condition of being dark or dim. [3 definitions] |
| obsequious |
showing or tending to show servile obedience or deference; fawning. |
| obsequy |
(usu. pl.) a funeral rite or ceremony. |
| observable |
able to be observed; visible. [2 definitions] |
| observance |
compliance or obedience. [4 definitions] |
| observant |
watching carefully; alert; attentive. [2 definitions] |
| observation |
the act or an instance of observing. [5 definitions] |
| observation car |
a railway car with large windows from which passengers may observe the scenery. |
| observation post |
a forward military position from which the enemy can be observed and artillery fire can be directed. |
| observatory |
a building containing equipment for making astronomical or other kinds of scientific observations. |
| observe |
to perceive; see. [10 definitions] |
| observer |
someone who observes an event such as a meeting but does not participate in it. [2 definitions] |
| obsess |
to preoccupy the mind or emotions of (someone) excessively or abnormally. |
| obsession |
that which preoccupies one's mind or emotions excessively or abnormally. [2 definitions] |
| obsessive |
of, pertaining to, characterized by, or causing an obsession. |
| obsessive-compulsive |
of or relating to having unwanted and uncontrollable thoughts (obsessions), and engaging in repetitive and uncontrollable behaviors (compulsions). [3 definitions] |
| obsessive-compulsive disorder |
a mental disorder characterized by having unwanted and uncontrollable thoughts (obsessions), and/or engaging in repetitive and uncontrollable behaviors (compulsions); OCD. |
| obsessive-compulsive neurosis |
an emotional disorder characterized by compulsions, irresistible urges, or both, and often manifested in ritualistic behavior. |
| obsidian |
a dark, shiny volcanic glass, often used in jewelry, that fractures in a smooth, shell-like curve. |
| obsolesce |
to become or be in the process of becoming obsolete. |