Mature, grown-up, old enough (with the implication that one can look after oneself and make one's own decisions).
Having an easy or accepting relationship with something.
Generally warm, approachable and easy to relate with in character.
Inviting, characteristic of friendliness.
Without any hostility.
Of or pertaining to friendlies (friendly noun sense 2, below). Also applied to other bipolar confrontations, such as team sports.
Compatible with, or not damaging to (the compounded noun).
Promoting the good of any person; favourable; propitious.
Being or relating to two or more natural numbers with a common abundancy.
A person or entity on the same side in a conflict.
A game which is of no consequence in terms of ranking, betting etc.