Pass muster means to be acceptable, to sufficiently meet expectations. Pass muster is an idiom that has its roots in military parlance. Muster means to assemble a group of men for a variety of reasons, including inspection. If one passed inspection in an acceptable manner, then one passed muster. Related terms are passes muster, passed muster, passing muster. The word muster comes from the Old French word mostrer, which means to show or reveal.
Pass mustard is an eggcorn, which is a misunderstand or mishearing of a word or phrase. Occasionally, pass mustard may be used for comic effect, but is not considered a grammatically correct term.
Simply being frustrated that someone else has suffered an injury doesn’t pass muster and will get dropkicked out of court as quickly as it was filed. (The Boston Herald)
Many did not pass muster because of the deep-fried angle- cavemen certainly did not have access to big cans of vegetable oil! (The Hindu)
But sometimes, a cat or dog simply doesn’t pass muster and become stage-ready. (The Press of Atlantic City)
Two Republicans who are also doctors — Reps. Larry Bucshon of Indiana and Andy Harris of Maryland — raised doubts about whether the consent forms would pass muster with a hospital or university Institutional Review Board (IRB). (The Washington Times)
The film could have easily passed muster as a dry technical showcase, but Favreau gives it real analogue earth-under-the-fingernails charm. (The Telegraph)
The beef pot roast (a flat iron cut) with spag pomodoro would have passed muster with an Italian nonna. (The Vancouver Sun)
Design plans for the possible construction of a Dollar General store in Loma Rica passed muster with the Yuba County planning commission over the objections of several community residents. (The Appeal Democrat)