Anki
For very low frequency words there is really no other way outside of reading a lot of texts in which their use is more frequent

Slowly, and then all at once

>>24966559
Don't do it intentionally, you'll end up using words which sound forced and out of context

>>24966559
Just read and look up words you don't know. There is no practical point in learning niche words because other people won't understand you. In their ignorance, they will assume you are an out-of-touch intellectual. Instead, learn to wield the smaller toolkit with greater mastery.

Read classics written by neurotic women for purple prose

Read the dictionary. The A section is quite boring though, I recommend starting with C, it makes me feel quite coxcombical

prompt too vague, depends on intended purposes
learning to simply recognize words as valid according to a dictionary (that is, Scrabble usage) admits of training methods not suitable for other uses
learning to apply technical terms / domain-specific language also requires a different sort of approach, since that involves detailed functions of interrelated components: being able to define each of the words of a discipline in isolation doesn't by itself indicate or confer conceptual or operational knowledge
you also haven't described any starting conditions/assumptions: age, level of ability, first language or foreign language, etc.

you should start by learning to ask better questions

>>24966666
Kek agrees, crack an austen

>>24966559
vocabulary is secondary to good prose and rhetorical technique. a grandiloquent effivacity of loquacious perspicacity will win you few friends.

look up word of the year
this year it's 'slop"
last year it was "blackyxsicopter" and "woe-man"