a printed punctuation mark (‽), available only in some typefaces, designed to combine the question mark (?) and the exclamation point (!), indicating a mixture of query and interjection, as after a rhetorical question.
an extraordinary or unusual thing, person, or event; an exceptional example or instance.
c.1422, from M.Fr. instabilite, from L. instabilitatem (nom. instabilitas) "unsteadiness," from instabilis "unsteady," from in- "not" + stabilis (see stable (2)).