of, pertaining to, characteristic of, or resembling a rat
2.
infested with rats
Word origin
[1680–90; rat + -ish1]This word is first recorded in the period 1680–90. Other words that entered Englishat around the same time include: bull's-eye, commercial, gangway, reservoir, turnoff-ish is a suffix used to form adjectives from nouns, with the sense of “belonging to”(British; Danish; English; Spanish); “after the manner of,” “having the characteristics of,” “like” (babyish; girlish; mulish); “addicted to,” “inclined or tending to” (bookish; freakish); “near or about” (fiftyish; sevenish)