expatiate

From the participle stem of Latin expatior, from ex- + spatior (“walk about”).

• IPA^(key): /ɛkˈspeɪʃɪeɪt/

expatiate (third-person singular simple present expatiates, present participle expatiating, simple past and past participle expatiated)

1. (now rare) To range at large, or without restraint.
   • 1717, Alexander Pope, “Windsor-Forest”, in The Works of Mr. Alexander Pope, volume I, London: Printed by W[illiam] Bowyer, for Bernard Lintot, […], OCLC 43265629, page 62:

     [L]ooks on heav'n with more than mortal eyes, / Bids his free ſoul expatiate in the skies, / Amidſt her kindred ſtars familiar roam, / Survey the region, and confeſs her home! Such was the life great Scipio once admir'd, / Thus Atticus, and Trumball thus retir'd.

2. To write or speak at length; to be copious in argument or discussion.

   Synonyms: descant, dilate, enlarge, expound

   • 1851, Herman Melville, Moby Dick, chapter 35

     Now, as the business of standing mast-heads, ashore or afloat, is a very ancient and interesting one, let us in some measure expatiate here.

   • (Can we date this quote by Addison?)

     He expatiated on the inconveniences of trade.

   • 1992 May 3, "Comrade Bingo" Jeeves and Wooster, Series 3, Episode 6:

     WOOSTER: If you ask me, art is responsible for most of the trouble in the world.
     JEEVES: An interesting theory, sir. Would you care to expatiate upon it?
     WOOSTER: As a matter of fact, no, Jeeves. The thought just occurred to me, as thoughts do.
     JEEVES: Very good, sir.

   • 2007, Clive James, Cultural Amnesia (Picador 2007, p. 847)

     “It can't fly,” he expatiated. “It can move forward only by hopping.”

3. (obsolete) To expand; to spread; to extend; to diffuse; to broaden.