The most embarrassing thing is I can’t even remember what the term was - I think it was
per mufti
but it might have been
per tufti or per pufti
or some other mutation. I encountered it in a documentary about Ben Franklin - he was, ca. 1754, a colonel of a Pennsylvania militia, and when they marched out of Philadelphia, Ben went per mufti.
From context, I think it meant something to do with the way he dressed - either civilian clothes, or in a simple uniform as opposed to a rakish one with a sash.
Mufti has two main meanings: an Islamic scholar entitled to interpret the sharia and to issue a fatwa; and civilian dress worn by a military person or other person entitled to wear a uniform. According to Michael Quinion, the term derives from the casual wear of officers’ clubs, officers’ messes, etc., in the British Indian Army. The dressing gown and slippers acceptable for officers relaxing in the evening brought to mind the normal costume of the muftis. It was later extended to the wearing of any civilian clothing by someone in the military. In the documentary, Ben was therefore described as going in civilian clothes even though entitled to wear a uniform.