Kangaroo word: infantile
Joey word: inane
Definitions in relation to their use in kangaroo words, taken from Google Dictionary, and edited for formatting.
infantile (adjective): of or occurring among babies or very young children.
inane (adjective): silly.
The letters I, N, A, N, and E found within the kangaroo word “infantile” arrange in the listed order to complete the joey word “inane”. While a word can have multiple definitions, in relation to their use with kangaroo words, these two words share a similar meaning: to act childish.