How Well Do You Know English Slang?
"confusedly," 1570s, from Middle French pêle-mêle, from Old French pesle mesle (12c.), apparently a jingling rhyme on the second element, which is from the stem of the verb mesler "to mix, mingle" (see meddle). Phonetic French form pelly melly is attested in English from mid-15c.
In a confused, disorderly manner: “After the assembly, the students ran pell-mell from the auditorium.”