simple

Synonyms: child’s play cinch clean easy as pie effortless elementary facile incomplex intelligible light lucid manageable mild no problem no sweat not difficult picnic piece of cake plain quiet self-explanatory simple as abc smooth snap straightforward transparent uncomplicated uninvolved unmistakable untroublesome walkover

Antonyms: complex complicated convoluted difficult exacting intricate unclear unintelligible

Synonyms: absolute austere classic clean discreet elementary folksy homely homey humble inelaborate lowly mere modest not complex open and shut plain pure pure and simple rustic sheer single spartan unadorned unadulterated unaffected unalloyed unblended uncombined uncomplicated uncompounded undecorated unelaborate unembellished unfussy unmitigated unmixed unornamented unostentatious unpretentious unqualified vanilla

Antonyms: cluttered decorated embellished jumbled ornate

Synonyms: amateur artless bald basic childish direct frank green guileless honest ingenuous naive naked natural plain sincere square stark trusting unaffected unartificial undeniable unexperienced unpretentious unschooled unsophisticated unstudied unvarnished

Antonyms: mature older sophisticated

Synonyms: amateur asinine backward brainless credulous dense dimwitted dull dumb fat feeble foolish green gullible half-witted idiotic ignorant illiterate imbecile inane inexperienced inexpert insensate mindless moronic nitwitted obtuse senseless shallow silly simpleminded slow soft soft-headed stupid thick uneducated unintelligent witless

Antonyms: aware intelligent on-the-ball smart