Will could not resist this imperturbable temper, and the cloud in his face broke into sunshiny laughter.
Mr. Cadwallader was a large man, with full lips and a sweet smile; very plain and rough in his exterior, but with that solid imperturbable ease and good-humor which is infectious, and like great grassy hills in the sunshine, quiets even an irritated egoism, and makes it rather ashamed of itself.
From the earliest to the latest hour of the day he was always as sleek, neat, and cool as the frog he resembled, and old Peter had secretly chuckled over an offshoot almost more calculating, and far more imperturbable, than himself.
There are no more uses of "imperturbable" in the book.
Show samples from other sources
Silas was imperturbable.
Neil Gaiman -- The Graveyard Book
Out of loudspeakers all around Zollverein, the staccato voice of the Reich grows like some imperturbable tree; its subjects lean toward its branches as if toward the lips of God.