As adjectives the difference between rattish and fattish
is that rattish is pertaining to rats or rattish can be slightly short-tempered while fattish is somewhat fat.
rattish
English
Etymology 1
Adjective
(
en adjective)
pertaining to rats
exhibiting qualities that are commonly associated with rats.
Etymology 2
Adjective
(
en adjective)
slightly short-tempered
slightly run-down or dilapidated
Anagrams
*
*
* fattish
English
Adjective
(-)
Somewhat fat