ad. Without a method; in a confused or unsystematic manner.
the GNU version of the Collaborative International Dictionary of English
ad. Without method; confusedly; unsystematically.
The Century Dictionary and Cyclopedia
In an immethodical manner; without order or regularity; irregularly.
Word Usage
"Ovid's "Metamorphoses," translated by several hands; which he recommended by a preface, written with more ostentation than ability; his notions are half-formed, and his materials immethodically confused."