Facile

1. Easy, now especially in a disparaging sense; contemptibly easy. [from 15th c.]
2. (now rare) Amiable, flexible, easy to get along with.
3. Effortless, fluent (of work, abilities etc.). [from 17th c.]
4. Lazy, simplistic (especially of explanations, discussions etc.). [from 19th c.]
5. (chemistry) Of a reaction or other process, taking place readily.