Avoid repetition
the technique of using different words/structures to express the same idea
Cross-reference
to refer back to something already mentioned using pronouns or connectors
Hyponym
a word that is more specific than a more general word (its hypernym)
Hypernym
a word whose meaning includes the meanings of other more specific words
Examples
Instead of repeating "important", use "crucial", "vital", or "key".
The study was published in 2020. It showed remarkable results. ("It" = the study)