1not affected by alcohol; not drunk.
2serious, sensible, and solemn:a sober view of life his expression became sober muted in colour:a sober grey suit
make or become sober after drinking alcohol: [with object]:that coffee sobered him up [no object]:I ought to sober up a bit make or become more serious, sensible, and solemn: [no object]:his expression sobered her (as adjective sobering)a sobering thought