英语词源字典 - 在线词源网站

calculating (adj.)[calculating 词源字典]: 1710, "carrying out calculations," present participle adjective from calculate. Meaning "shrewdly or selfishly seeking advantage" is attested from c. 1810.[calculating etymology, calculating origin, 英语词源]
operator (n.): 1590s, "one who performs mechanical or surgical operations," agent noun from operate (v.) or from Late Latin operator. Meaning "one who carries on business shrewdly" is from 1828. Specific sense of "one who works a telephone switchboard" (1884) grew out of earlier meaning "one who works a telegraph" (1847).
shrewd (adj.): c. 1300, "wicked, evil," from shrewe "wicked man" (see shrew). Compare crabbed from crab (n.), dogged from dog (n.), wicked from witch (n.). The sense of "cunning" is first recorded 1510s. Related: Shrewdly; shrewdness. Strutt's "Sports and Pastimes of the People of England" (1801) has a shrewdness of apes for a company or group of them. Shrewdie "cunning person" is from 1916.