Solution

RUDIMENTARY

3 clues

Basic

Word class: Common adjective
Nature of clue: Synonym
Difficulty: Very easy

Other solutions to Basic

Elementary

Word class: Common adjective
Nature of clue: Synonym
Difficulty: Easy

Other solutions to Elementary

Simple

Word class: Common adjective
Nature of clue: Synonym
Difficulty: Very easy

Other solutions to Simple

Words are categorized by artificial intelligence: there can be mistakes.