Kangaroo words are words that contain a synonym (called a joey word) within them, where the letters of the joey word appear in the same order as they do in the larger word. Here are several examples:
Masculine → Male
Observe → See
Blossom → Bloom
Encourage → Urge
Contaminate → Taint
Friend → Fiend
Illustrious → Lustrous
Feasting → Eating
Enlighten → Lighten
Instructor → Tutor
Each joey word hides within its parent kangaroo word, carrying a similar meaning.