How to add field array?

Situation

Hello everyone, Thanks for your time!

I want to make a template which can display a example paragraph with multiple new words to learn.
Like I read the news today, and find some words I don’t recognize, So I write down to memorize.

However, a paragraph can contain lots of new words, which you can’t count the number precisely.
So, how can I solve this problem? I may have some solutions, but I don’t know which will work.

May Solutions

  1. Define enormous fields for future using. I can define 10 word fields even if there are only 3 new words.
  2. Temporary add fields for a single card, I don’t know if this works.
  3. Write an addon, which can define a field as an structure array.

Effect

  1. Index every new words.
  2. I can click a new word to show the meaning.