simple
sim-ple
adjective
Easily understood, done, or used; not complicated or difficult.
"The instructions were very simple."
adjective
Lacking intelligence, common sense, or sophistication; foolish.
"Don't be so simple; it's obvious."
adjective
Plain, unadorned, or not elaborate in style or design.
"She preferred a simple, elegant dress."
Thesaurus
Synonyms: wide-eyed, round-eyed, naive, childlike, naif, dewy-eyed, easy, elementary, unproblematic, uncomplicated, undecomposable, simplex