Definitions in relation to their use in these kangaroo words, taken from Google Dictionary, and edited for formatting.
Kangaroo word: courteous
Joey word: curt
courteous (adjective): polite, respectful, or considerate in manner.
curt (adjective): rudely brief.
The letters C, U, R, and T found within the anti-kangaroo word “courteous” arrange in the listed order to complete the joey word “curt”. While a word can have multiple definitions, in relation to their use with kangaroo words, these two words share an opposite meaning: polite vs. rude.