expatiate \ek-SPAY-shee-ayt\, intransitive verb:
1. To speak or write at length or in considerable detail.
2. To move about freely; to wander.
He had told her all he had been asked to tell--or all he
meant to tell: at any rate he had been given abundant
opportunity to expatiate upon a young man's darling
--Henry Blake Fuller, Bertram Cope's Year
At the midday meal on fair day, a large one (meat loaf,
boiled potato, broccoli), Mrs. Lucas, married to the man
with the earache, expatiates on the difficulties of caring
for a parakeet her daughter has unloaded upon her and
which, let out of its cage for an airing, has escaped
through the door suddenly opened by Mr. Lucas.
--William H. Pritchard, Updike: America's Man of Letters
His relationship with his family was for many years an
unhappy one, and he does not care to expatiate upon it.
--Barbara La Fontaine, "Triple Threat On, Off And Off-Off
Broadway," New York Times, February 25, 1968
Expatiate is from Latin expatiari, "to walk or go far and
wide," from ex-, "out" + spatiari, "to walk about," from