Verb
To range at large, or without restraint.
To enlarge in discourse or writing; to be copious in argument or discussion; to descant.
To expand; to spread; to extend; to diffuse; to broaden.
Source: Webster's dictionaryA painter must compensate the natural deficiencies of his art. He has but one sentence to utter, but one moment to exhibit. He cannot, like the poet or historian, expatiate. Joshua Reynolds
Awake my St John Leave all meaner things To low ambition, and the pride of kings. Let us, since life can little more supply Than just to look about us and to die, Expatiate free o'er all this scene of man A mighty maze but not without a. Alexander Pope
She elaborated on the main ideas in her dissertation Source: Internet
This view might well be admitted by Gibbon himself: "But it is not my intention to expatiate with the same minuteness on the whole series of the Byzantine history." Source: Internet
It is useless to expatiate on its disadvantages. Source: Internet