Noun:
1: simple any herbaceous plant having medicinal properties
2: simpleton, simple a person lacking intelligence or common sense
Adjective:
1: unanalyzable, unsophisticated, undecomposable, simplex, uncomplicated, simple having few parts; not complex or complicated or involved; "a simple problem"; "simple mechanisms"; "a simple design"; "a simple substance"
2: unproblematic, easy, simple, uncomplicated, elementary easy and not involved or complicated; "an elementary problem in statistics"; "elementary, my dear Watson"; "a simple game"; "found an uncomplicated solution to the problem"
3: mere, plain, simple, bare apart from anything else; without additions or modifications; "only the bare facts"; "shocked by the mere idea"; "the simple passage of time was enough"; "the simple truth"
4: naive, childlike, dewy-eyed, simple, naif, round-eyed, wide-eyed exhibiting childlike simplicity and credulity; "childlike trust"; "dewy-eyed innocence"; "listened in round-eyed wonder"
5: dim-witted, simple, simple-minded, retarded, half-witted lacking mental capacity and devoid of subtlety
6: three-needled, needled, orbiculate, reniform, four-needled, orbicular, perfoliate, lanceolate, dolabrate, needle-shaped, obtuse, lancelike, spearhead-shaped, unsubdivided, cordiform, pandurate, five-needled, sagittiform, swordlike, acerose, ovate, hastate, elongate, arrow-shaped, oblong, shield-shaped, kidney-shaped, linear, simple, cuneate, spatulate, elliptic, apiculate, dolabriform, lyrate, cordate, acicular, spatula-shaped, deltoid, wedge-shaped, oblanceolate, fiddle-shaped, heart-shaped, sword-shaped, panduriform, peltate, caudate, acerate, sagittate, unlobed, ensiform, bladelike, obovate, two-needled, acuminate (botany) of leaf shapes; of leaves having no divisions or subdivisions
7: plain, simple unornamented; "a simple country schoolhouse"; "her black dress--simple to austerity"