The incorrectly spelled word is:

☀ kengaroo

The correct spelling is "kangaroo." Kangaroo is a large marsupial native to Australia.

The other options are spelled correctly:

• Vivacious: Means lively, full of energy and enthusiasm.
• Ambiguous: Means having more than one possible meaning or interpretation.
• Itinerary: Refers to a planned route or journey, especially when traveling.