Expatiate Ex*pa"ti*ate, v. i. [imp. & p. p. Expatiated; p. pr. & vb. n. Expariating.] [L. expatiatus, exspatiatus, p. p. of expatiari, exspatiari, to expatiate; ex out + spatiari to walk about spread out, fr. spatium space. See Space.] 1. To range at large, or without restraint. Bids his free soul expatiate in the skies. --Pope. 2. To enlarge in discourse or writing; to be copious in argument or discussion; to descant. He expatiated on the inconveniences of trade. --Addison.