swear like a trooper, to

swear like a trooper

To use profanities or vulgar language very freely and fluently. (An allusion to the rough language presumed to be used by military personnel.) My granny is the sweetest old lady you'll ever meet, but she swears like a trooper when she gets on the topic of something or someone she doesn't like.
See also: like, swear, trooper
Farlex Dictionary of Idioms.

swear like a trooper

to curse and swear with great facility. (The trooper here refers to a soldier.) Mrs. Wilson was known to swear like a trooper on occasion. The clerk started swearing like a trooper, and the customer started crying.
See also: like, swear, trooper
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

swear like a trooper

Freely utter profanity or obscenity, as in The teacher was shocked when she heard one of the fathers begin to swear like a trooper. The troopers in this term were the cavalry, who were singled out for their swearing from the early 1700s on.
See also: like, swear, trooper
The American Heritage® Dictionary of Idioms by Christine Ammer.

swear like a trooper

If someone swears like a trooper, they swear a lot. Mo was rude and abusive and swore like a trooper. Note: Nouns such as sailor or marine are sometimes used instead of trooper. The show has a heroine who drinks like a fish and swears like a sailor. Note: A trooper is a soldier.
See also: like, swear, trooper
Collins COBUILD Idioms Dictionary, 3rd ed.

swear like a trooper

swear a great deal.
A trooper was originally a private soldier in a cavalry unit. Troopers were proverbial for their coarse behaviour and bad language at least as early as the mid 18th century: in Pamela ( 1739–40 ), Samuel Richardson writes ‘she curses and storms at me like a Trooper’. Compare with lie like a trooper (at lie).
See also: like, swear, trooper
Farlex Partner Idioms Dictionary

swear like a ˈtrooper

(old-fashioned, British English) use many swear words; use bad language: She’s only fourteen, but she swears like a trooper.
A trooper is a soldier.
See also: like, swear, trooper
Farlex Partner Idioms Dictionary

swear like a trooper

in. to curse and swear with great facility. The clerk started swearing like a trooper, and the customer started crying.
See also: like, swear, trooper
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions

swear like a trooper, to

To spew forth profanity and/or obscenity. The troopers in question were the cavalry, who probably were no more apt to swear than other military men. Nevertheless, they were singled out from the early eighteenth century on, beginning with the unknown author of The Devil to Pay at St. James’s (1727).
See also: like, swear
The Dictionary of Clichés by Christine Ammer
See also:
  • a tough cookie
  • a tough customer/cookie
  • appear to
  • a change of heart
  • a mystery to (one)
  • be in high spirits
  • be in high/low spirits
  • be in low spirits
  • a turn of phrase
  • able to do