"a thing," indefinitely, late Old English aniþing, from any + thing. But Old English ænig þinga apparently also meant "somehow, anyhow" (glossing Latin quoquo modo).

"one indifferent to religious creeds, one 'that always make their interest the standard of their religion,'" 1704, originally dismissive, from anything on model of trinitarian, unitarian, etc.

"small brick" of anything, 1924; see briquette.

"the least part of anything," 1520s, from Latin iota, from Greek iota "the letter -i-," the smallest letter in the Greek alphabet, also "the least part of anything" (see iota). Usually (and originally) with tittle, from Matthew v.18.

"state of being exotic; anything exotic," 1827, from exotic + -ism.

"anything associated with the number six," by 1849, from six.

"one to whom anything is addressed," 1810; see address (v.) + -ee.

"anything that causes injury, anything that harms or is likely to harm; a malady or disease; conduct contrary to standards of morals or righteousness," Old English yfel (see evil (adj.)).

"the best (of anything)," 1709, originally slang, agent noun from top (v.).

"instrument for applying anything," 1650s, agent noun from Latin stem of apply (v.).