Graded and ungraded adjectives
The 'primary' group
These adjectives indicate that something is the most important part of something. We include here secondary, which indicates that something is the second most important part of something.
chief key main major primary prime principal secondary ultimate
Jeffrey Cooper described himself as a key figure in the protest movement.
Most of the checkpoints are on border roads, with the primary purpose of screening the large volume of traffic passing between north and south.