These words refer to things of overwhelming size, scale or weigh. Most concretely, massive indicates a large mass, bulk or weight: a massive boulder. Weight or bulk need not be implied, however, when the word points instead to something that is imposing or impressive in scale, scope, degree or intensity: a massive painting; a decision that was to have massive consequences throughout the succeeding century. In a medical sense, the word points to something extending over or affecting a large area: massive swelling.

Ponderous and hefty are more restricted than massive in that both echo the stress on weight but put less emphasis on sheer size. Relatively formal, ponderous points to heaviness that may be unwieldy or unbearable: pyramids made of ponderous stones that had to be inched into place. More often the word is used abstractly of something over-serious or solemn to the point of dullness: a ponderous lecture on the growing immorality of present-day society. The word can also suggest a heavy sort of physical movement that is slow, tortuous or lumbering: shuffling forwards with a ponderous gait. Relatively informal, hefty can refer more readily to physical heaviness, as of a physique: a hefty weight-lifter. Its unique area of relevance is to something that is heavy but meant to be picked up and carried: grunting as he lifted the hefty suitcase.

Huge and enormous contrast with the previous words in stressing sheer size more than heaviness per se. In this sense, both can serve as superlatives for large, with enormous being the more formal of the two. In itself, huge may suggest a looming tallness or largeness of frame: the huge football player; the huge balloon that they inflated for the aerial show. Enormous suggests extension in space on a scale that goes beyond the implications of huge : the huge man dwarfed by the enormous room. Both words can be used metaphorically for something serious, critical or urgent: the huge problems that must be faced if the population explosion is to be checked; enormous questions that remain to be answered. Enormous , however, may carry implications over from the word enormity in the sense of something abnormal, grotesque or outrageous: enormous crimes committed in the name of justice.

Immense is like the previous pair in stressing size more than weight; where it refers to material masses, the word suggests something dramatically or surprisingly of large scale: an immense statue, a hundred times life size. But the word frequently stresses, like enormous , extension in space, rather than mass: early explorers who got lost in the immense , uncharted Atlantic. Often, the word relates to totally non-material or spiritual entities, with the implication of proportions so great as to swallow up things of normal scale: the immense void between the Milky Way and its nearest galactic neighbour. Vast concentrates exclusively on extension in space, with a complete absence of implications pertaining to weight or even to measurable or definable size: the vast emptiness of the unending desert. In comparison with immense , which can suggest three-dimensional largeness, vast more readily suggests two-dimensional extension: the immense volume enclosed by the cathedral’s domed nave; the vast lawns surrounding Government House.