泰然自若

たいぜんじじゃく

taru-adjective, to-adverb

•

having presence of mind, self-possessed, imperturbable, calm and self-possessed(yojijukugo)

泰	peaceful, calm, peace, easy, Thailand, extreme, excessive, great
然	sort of thing, so, if so, in that case, well
自	oneself
若	young, if, perhaps, possibly, low number, immature