Not fastened, restrained, or contained: loose bricks. Not taut, fixed, or rigid: a loose anchor line; a loose chair leg. Free from confinement or imprisonment; unfettered: criminals loose in the neighborhood; dogs that are loose on the streets. Not tight-fitting or tightly fitted: loose shoes. Not bound, bundled, stapled, or gathered together: loose papers. Not compact or dense in arrangement or structure: loose gravel. Lacking a sense of restraint or responsibility; idle: loose talk. Not formal; relaxed: a loose atmosphere at the club. Lacking conventional moral restraint in sexual behavior. Not literal or exact: a loose translation. Characterized by a free movement of fluids in the body: a loose cough; loose bowels. In a loose manner. To let loose; release: loosed the dogs. To make loose; undo: loosed his belt. To cast loose; detach: hikers loosing their packs at camp. To let fly; discharge: loosed an arrow. To release pressure or obligation from; absolve: loosed her from the responsibility. To make less strict; relax: a leader's strong authority that was loosed by easy times. To become loose. To discharge a missile; fire. on the loose At large; free. on the loose Acting in an uninhibited fashion.