equable

adj.

[1]	even-tempered , easygoing , serene , calm , placid , composed , cool , imperturbable , collected , unruffled , tranquil , peaceful , level-headed , (Colloq) unflappable
[2]	uniform , even-tempered , good-tempered , unvarying , unvaried , placid , consistent , stable , steady , regular , even , unchanging , invariable , constant