Noun:
1: simple any herbaceous plant having medicinal properties
2: simpleton, simple a person lacking intelligence or common sense
Adjective:
1: simplex, undecomposable, unanalyzable, unsophisticated, uncomplicated, simple having few parts; not complex or complicated or involved; "a simple problem"; "simple mechanisms"; "a simple design"; "a simple substance"
2: elementary, easy, simple, uncomplicated, unproblematic 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: simple, plain, mere, 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: dewy-eyed, round-eyed, naive, naif, simple, wide-eyed, childlike exhibiting childlike simplicity and credulity; "childlike trust"; "dewy-eyed innocence"; "listened in round-eyed wonder"
5: retarded, half-witted, simple, dim-witted, simple-minded lacking mental capacity and devoid of subtlety
6: dolabriform, wedge-shaped, obovate, lanceolate, two-needled, simple, four-needled, pandurate, reniform, sagittiform, acerate, ovate, cordate, apiculate, acerose, spatula-shaped, needled, needle-shaped, arrow-shaped, cordiform, heart-shaped, caudate, swordlike, elongate, deltoid, peltate, sword-shaped, spearhead-shaped, oblanceolate, unsubdivided, bladelike, hastate, dolabrate, kidney-shaped, fiddle-shaped, lyrate, acicular, sagittate, unlobed, elliptic, orbiculate, cuneate, linear, lancelike, five-needled, spatulate, perfoliate, orbicular, shield-shaped, acuminate, three-needled, obtuse, ensiform, panduriform, oblong (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"