Etymonline does not hesitate to assume that "a pride of lions" is the same word as pride, noun of adjective proud.
There would be other possibilities, e.g. a connection with Latin praeda (prey). A group of lions might be a group of animals that go hunting together to get their prey.
Another possibility is Latin parata, past participle of parare (to prepare). A group of lions might be a group a dominant male animal has prepared for itself as its group.
Do we have here some specialists for etymology who might give their view as to
- pride of lions connected with proud/pride (convincing or not) –
- other possibilities.
Best Answer
The simplest argument in favour of the conventional view; that pride in this sense is a use of the same word that refers to the quality of being proud, is that it is in keeping with many other such words for animals:
These are similarly qualities that involve a noun normally taken to refer to a quality humans may possess, and turning them to use as a collective noun.
All four here are from the 1486 Boke of Seynt Albans, as indeed is "pride of lions". The Modern Language Association of America apparently has a record of the use from around 1450, so the Book of St. Albans is not the first, but was one of the first records.
And considering that it also has such entries as "a doctrine of doctors" and "A disworship of Scots" it's clear that the practice of creating humorous versions of such collective nouns ("a click of web developers", "a promise of politicians", etc.) is nothing new. Humour has in fact always been part of the inspiration behind such names. More generally than that, there was always an element of word-play.
And there was again when such words were revived, having dropped out of use for several centuries but then revitalised because they are amusing, and because they provided a sort of vicarious knowledge; things one can know whose value is largely in enjoying knowing them. (Most subcultures today have these, the person who looks down upon the person who can recollect the comic book issue in which a particular superhero made his first appearance taking pride in knowing the scores of every final in a particular sport, and so on).
There are some such nouns that relate more directly to the behaviour of the actual animal itself, than to such personalised traits, so your suggestions cannot be fully ruled out.
However, these "traditional" collective nouns came into being in 15th century England, where a lion was much more often seen on a flag or a crest, than on a savannah, and where it was indeed associated with pride.
Lions were previously used as an image of the sin of pride, as in this Book of Hours from circa 1475 where a personification of Pride rides on a lion's back:
This makes the idea that the association was indeed with the quality of being proud, the most likely.