Solution

INTEGRAL

4 clues

Built-in

Word class: Common adjective
Nature of clue: Synonym
Difficulty: Easy
Sources: Boatload Puzzles

Other solutions to Built-in

Essential

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

Other solutions to Essential

Key

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

Other solutions to Key

Necessary

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

Other solutions to Necessary

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