not difficult to understand or do
simple
difficult to do or understand
complicated
unsafe, may cause serious injury or accident
dangerous
being protected and free from danger
safe
not in a place or a class
absent
at a place or in a class
present
not old, has not existed for a long time
young
grown-up physically or mentally
mature
the direction in front of you
forward
the direction behind you
backward
very clever or smart, can understand complicated things
intelligent
silly and not very thoughtful
foolish
