noun

1. SIMPLE, a person lacking intelligence or common sense
2. SIMPLE, any herbaceous plant having medicinal properties

adjective

1. SIMPLE, easy and not involved or complicated
2. SIMPLE, apart from anything else; without additions or modifications
3. SIMPLE, unornamented
4. SIMPLE, lacking mental capacity and subtlety
5. SIMPLE, exhibiting childlike simplicity and credulity

adjective

1. SIMPLE, (botany) of leaf shapes; of leaves having no divisions or subdivisions
2. SIMPLE, having few parts; not complex or complicated or involved

1. The solution to the problem was relatively simple.
2. The answer is really quite simple.
3. There are three simple steps to follow.