Definitions in relation to their use in these kangaroo words, taken from Google Dictionary, and edited for formatting.
Kangaroo word: iconoclast
Joey word: icon
iconoclast (noun): a person who attacks cherished beliefs or institutions.
icon (noun): a person or thing regarded as a representative symbol or as worthy of veneration.
The letters I, C, O, and N found within the anti-kangaroo word “iconoclast” arrange in the listed order to complete the joey word “icon”. While a word can have multiple definitions, in relation to their use with kangaroo words, these two words share an opposite meaning: a critic vs. an idol.