even-tempered
adjective
• not easily annoyed or made angry.
• "he was a gentle and even-tempered man"
Similar:
serene,
calm,
composed,
poised,
tranquil,
relaxed,
easy-going,
mild,
mellow,
unworried,
untroubled,
unbothered,
unruffled,
unflustered,
unexcitable,
imperturbable,
placid,
equable,
stable,
well balanced,
level-headed,
unflappable,
together,
laid-back,
unfazed,
equanimous,