(Intransitive, slang, often with "to") To see through deceit.
Tumble is defined as to do somersaults, fall clumsily or stumble, or to cause someone or something to fall.
To observe or notice.
Find another word for cotton-on. In this page you can discover 7 synonyms, antonyms, idiomatic expressions, and related words for cotton-on, like: catch on, get-wise, get-onto, tumble, latch-on, twig and get-it.