A word of warning on these: one thing I've learned while reading the divine Jane, or indeed anyone of her antiquity, is that using a modern dictionary to see what their words mean can be very misleading. The best option would be to use Johnson's famous dictionary. (The link below is to the 6th edition of 1785.) In JA's time, this work was already the classic of English lexicography, having the same status as the Oxford English Dictionary does now, at least in the UK, and any definition in that work would have been fairly close to the meaning she would have had in mind. However, words constantly change their meanings, even in the short space of time between Johnson's lifetime and JA's, so you can't be too careful. I'm using the Cambridge edition for this GR, which has copious notes (often several for each chapter) on such changes of meaning in the last 200 years.

In this particular case, "caprice" is fairly close to its modern usage: Johnson gives it as "Freak; fancy; whim; sudden change of humour". One example of a word which now means something quite different occurs in the very same paragraph, the last one in Ch.1: "develope" (JA's spelling), which Johnson gives as "To disengage from something that enfolds and conceals; to disentangle; to clear from its covering". Its modern equivalent in this sense would be "discover or discern" rather than "build on or improve". In other words, Mrs Bennet had not managed to understand her husband's character in 23 years of marriage, but hers was much more obvious.