Noun:
1: simple any herbaceous plant having medicinal properties
2: simpleton, simple a person lacking intelligence or common sense
Adjective:
1: simplex, simple, undecomposable, uncomplicated, unsophisticated, unanalyzable having few parts; not complex or complicated or involved; "a simple problem"; "simple mechanisms"; "a simple design"; "a simple substance"
2: elementary, simple, easy, unproblematic, uncomplicated 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: plain, simple, 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: wide-eyed, dewy-eyed, naive, childlike, round-eyed, simple, naif exhibiting childlike simplicity and credulity; "childlike trust"; "dewy-eyed innocence"; "listened in round-eyed wonder"
5: retarded, simple, half-witted, dim-witted, simple-minded lacking mental capacity and devoid of subtlety
6: swordlike, deltoid, unsubdivided, hastate, acerate, orbicular, kidney-shaped, needled, lanceolate, five-needled, lyrate, perfoliate, arrow-shaped, oblanceolate, cordate, dolabriform, elongate, spatulate, orbiculate, fiddle-shaped, unlobed, panduriform, elliptic, cordiform, reniform, obtuse, caudate, wedge-shaped, spearhead-shaped, acicular, four-needled, needle-shaped, oblong, acuminate, ovate, sword-shaped, peltate, spatula-shaped, linear, sagittiform, pandurate, shield-shaped, simple, obovate, two-needled, apiculate, cuneate, bladelike, three-needled, acerose, heart-shaped, lancelike, dolabrate, ensiform, sagittate (botany) of leaf shapes; of leaves having no divisions or subdivisions
7: simple, plain unornamented; "a simple country schoolhouse"; "her black dress--simple to austerity"