consumptive adj.

late 14c., "to destroy by separating into parts which cannot be reunited, as by burning or eating," hence "destroy the substance of, annihilate," from Old French consumer "to consume" (12c.) and directly from Latin consumere "to use up, eat, waste," from assimilated form of com-, here perhaps an intensive prefix (see com-), + sumere "to take," from sub- "under" (see sub-) + emere "to buy, take" (from PIE root *em- "to take, distribute").

Specifically, "to destroy by use, wear out by applying to its natural or intended use" from c. 1400. Sense of "to engage the full attention and energy of" is from 1570s.

word-forming element making adjectives from verbs, meaning "pertaining to, tending to; doing, serving to do," in some cases from Old French -if, but usually directly from Latin adjectival suffix -ivus (source also of Italian and Spanish -ivo). In some words borrowed from French at an early date it has been reduced to -y (as in hasty, tardy).