Open English Wordnet
Adjectives
(s)uncomplicated, unsophisticatedlacking complexity“small and uncomplicated cars for those really interested in motoring”, “an unsophisticated machine”
(s)elementary, simple, uncomplicated, unproblematiceasy and not involved or complicated“an elementary problem in statistics”, “elementary, my dear Watson”, “a simple game”, “found an uncomplicated solution to the problem”