IPA: //ˈmʌltiˌtæskər//
KK: /mʌltiˌtæskər/
A person who is able to handle more than one task at the same time.
As a multitasker, she can answer emails while attending meetings.
Multitasker → It is formed from "multi-" (meaning many) and "task" (from Old Norse *taskr*, meaning a piece of work or duty) and "-er" (meaning a person who). The word describes a person who handles many tasks at once.
Think of someone managing 'many' ('multi-') 'pieces of work' ('task') — that's what a multitasker does.
No commonly confused words.