Size and shape; aesthetics

большой лоб; здоровый лоб Colloquial a large forehead
огромный лоб an enormous forehead
сократовский лоб a Socratic forehead
лобастый Substandard; большелобый having a large forehead
высокий лоб a high forehead
широкий лоб a broad forehead
NB The size and shape of a forehead are considered to reflect a person's intellectual properties. Therefore the corresponding expressions have connotations of intelligence or, on the contrary, stupidity, narrow-mindedness; the expressions большой, огромный, сократовский or высокий лоб, above, are associated with intelligence, while the expressions маленький, узкий or покатый лоб, below, are associated with stupidity.
небольшой лоб; маленький лоб a small forehead
низкий лоб; невысокий лоб a low forehead
Седые его волосы висели клочьями над невысоким лбом. [И. Тургенев, Дворянское гнездо] Wisps of grey hair hung over his low forehead. [I. Turgenev, A Nest of Gentlefolk]
низколобый having a low forehead
узкий лоб a narrow forehead
узколобый having a narrow forehead
NB The word узколобый is also used metaphorically to mean "narrow-minded." Cf. твердолобый, used only metaphorically, which means "hard-headed, stubborn."
крутой лоб a steep forehead
крутолобый having a steep forehead
выпуклый лоб a protuberant forehead
покатый лоб a sloping forehead
прямой лоб a straight forehead
гладкий лоб a smooth forehead
мраморный лоб a marble brow
чистый лоб a pure brow, usually a large, broad forehead with smooth skin
... веки его были чуть опущены, но лоб, чистый, мраморный, был невозмутим. [А. Битов, Уроки Армении] ... his eyelids were lowered a bit, but his pure marble brow was imperturbable. [A. Bitov, Lessons of Armenia]
ясный лоб a clear brow, indicating that its possessor is untroubled, unworried
безмятежный лоб Bookish a serene forehead
морщинистый лоб a wrinkled brow, a furrowed brow
морщины на лбуloc; складки на лбуloc wrinkles on one's forehead, brow
шишковатый лоб a bumpy forehead
открытый лоб an uncovered forehead, i.e. usually a high forehead without a scarf, bangs, etc. on it
лоб с залысинамиi a receding hairline
красивый лоб a pretty forehead
некрасивый лоб an unattractive forehead, an ugly forehead
умный лоб an intelligent forehead
лоб мыслителяg a thinker's brow
дегенеративный лоб a degenerate brow
упрямый лоб a stubborn forehead
белолобый having a star or blaze on its forehead
NB The above word is used only of animals with a star or blaze on their foreheads.