Bright, brilliant, radiant, luminous, lustrous, effulgent, refulgent, beaming, lambent, lucent, incandescent are comparable when they mean actually or seemingly shining or glowing with light.
Bright implies an opposition to dim or dull; it applies chiefly to things that vary in the degree in which they shed light or are pervaded by light, according to circumstances; thus, when used in reference to a fire or burning material (as coals), it suggests a good draft and flames; when used in reference to a day, it implies lack of clouds, fog, smoke, or other obstacles to the passage of sunlight.
Brilliant (see also INTELLIGENT) implies conspicuous or intense brightness; it also often connotes scintillating or flashing light.
Radiant, in contrast with bright and brilliant, stresses the emission or seeming emission of rays of light; it suggests, therefore, a property or power possessed by a thing rather than a quality ascribed to it because of its effect on the vision; thus, a celestial body is properly described as radiant only when it emits rays of light; a planet, no matter how bright it appears to the eye, is preferably described as bright or brilliant because it shines by reflected light.
The term, however, is sometimes used of anything that seems to give out light in the manner of the sun or a star.
Luminous, like radiant, suggests emission of light, but, unlike it, implies the sending forth of steady suffused glowing light; it is applicable to anything that shines by reflected light or that glows in the dark because of some special quality (as of physical state or chemical activity); thus, all celestial bodies are luminous, but only self-luminous bodies (stars in the strict astronomical sense) are also radiant.
As applied to color or to colored things the term implies more than bright, for it usually suggests a jewellike quality or iridescence.
As applied to ideas or their expression, the term implies crystallike clearness and the absence of all obscurity.
Lustrous is applied only to an object whose surface reflects light; it therefore seldom implies pervading light but, rather, a brilliant or iridescent sheen or gloss.
Effulgent and refulgent indicate resplendent or gleaming brilliance, and the latter implies further that the brilliance is reflected, sometimes from an unseen source.
Beaming literally implies emission of a beam (see beam under RAY).
In its commonest use (as applied to looks or expression) beaming suggests a display of happiness, satisfaction, or benevolence.
Lambent is applied to a thing (as a flame or a luminous body) which throws a play of light over an object or surface without rendering it brilliant or lustrous.
Often lambent suggests the emission of soft gleams of light.
Lucent is a highly poetical or literary adjective that approaches luminous or, less often, lustrous in its meaning; it is usually applied to something transfigured by light (as from the sun or a fire).
Incandescent suggests intense glowing brightness of or as if of an intensely heated body.