The word “onion” is pronounced as [ˈʌnjən]. The first sound is “uh” as in “up”. Then comes “n” sound. After that, “y” is pronounced like “i” in “in”. And finally, “ən” which sounds like “un” in “fun”. When you say it, make sure to pronounce each sound clearly and smoothly. For example, you can say “I like onions. Onions are used in many dishes.” Practice saying “onion” several times to get the pronunciation right.