greenier
Greenier is a rarely used, nonstandard comparative form of the adjective green. The standard comparative in English is greener. Greenier may appear in informal speech or creative writing, where a writer seeks to emphasize a stronger or more intense shade of green, but it is not widely accepted in formal or academic writing.
Origins and usage notes: The usual way to form the comparative of green is with -er, yielding
Context and examples: In everyday prose, most writers would choose greener to describe a more green color
Summary: Greenier is a stylistic, nonstandard variant of greener, used mainly for emphasis, humor, or poetic