conservative, low-key(also low-keyed), muted, quiet, repressed, restrained, sober, subdued, toned-down, understated, unpretentious

appropriate, becoming, fit, fitting, proper, suitablemodest, plain, simple, unadorned, undecoratedinconspicuous, unnoticeable, unobtrusivegraceful, handsome, refined, tastefuldrab, mousy(or mousey)practical, sensible

flamboyant, flaring, flashy, garish, gaudy, glitzy, loud, noisy, ostentatious, razzle-dazzle, splashy, swank(or swanky)

meretriciousgraceless, inelegant, tacky, tasteless, tawdry, trashy, vulgarbaroque, fancy, frilly, gilded(or gilt), ornate, rococooverdecorated, overdone, overwrought