dis·in·te·grate / disˈintəˌgrāt/ • v. [intr.] break up into small parts, typically as the result of impact or decay: when the missile struck, the car disintegrated in a sheet of searing flame. ∎ (of a society, family, or other social group) weaken or break apart: the marriage disintegrated amid allegations that she was having an affair. ∎ inf. deteriorate mentally or physically: I thought that when I finished working on the book I'd disintegrate. ∎ Physics undergo or cause to undergo disintegration at a subatomic level: [intr.] a meson can spontaneously disintegrate | [tr.] it has become a relatively easy matter to disintegrate almost any atom. DERIVATIVES: dis·in·te·gra·tive / -ˌgrātiv/ adj.dis·in·te·gra·tor / -ˌgrātər/ n.