mid-15c., perhaps frequentative of romen
"to walk, go" (see roam
), perhaps via romblen
(late 14c.) "to ramble." The vowel change probably by infl. of M.Du. rammelen,
a derivative of rammen
"copulate," "used of the night wanderings of the amorous cat" [Weekley]. Meaning "to talk or write incoherently" is from 1630s.