• (n.) Any agent that depresses the activity of the motor centers, as bromides, etc. • (a.) Depressing or diminishing the capacity for movement, as depressomotor nerves, which lower or inhibit muscular activity.
(de-pres″o-mo´tәr) retarding or abating motor activity. an agent that so acts.
De·pres`so·mo'tor adjective (Medicine) Depressing or diminishing the capacity for movement, as depressomotor nerves, which lower or inhibit muscular activity. -- noun Any agent that depresses the activity of the motor centers, as bromides, etc. 
causing a retardation of motor activity: depressomotor nerves.