draw the line at, to

draw the line at

Refuse to go any further than, as in I draw the line at giving them more money. This expression alludes to a line drawn at a stopping point of some kind. [Late 1700s]
See also: draw, line

draw the (or a) line at

set a limit of what you are willing to do or accept, beyond which you will not go.
1995 Kate Atkinson Behind the Scenes at the Museum She even manages to persuade Gillian not to cheat…although Gillian draws the line at not screaming when she loses.
See also: draw, line

draw the line at, to

To set a specific limit, particularly on one’s behavior. This expression, heard in such contexts as “He drew the line at outright cheating,” comes from drawing some sort of boundary, but no one is quite certain as to what kind. Some speculate it comes from the early game of court tennis, in which the court had no specific dimensions and the players had to draw their own lines. Others believe it signified a line cut by a plow across a field to designate the property boundary. The term was used figuratively from the late eighteenth century on and was probably a cliché by the time W. S. Gilbert wrote, “I attach but little value to rank or wealth, but the line must be drawn somewhere” (H.M.S. Pinafore, Act I).
See also: draw, line