Side Business, Side Job, Side Gig
noun
A side business is a side business.
ふくぎょう
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
副業で、中古のカメラを売り買いしています。
I buy and sell second-hand cameras on the side.
私の彼は副業でネットワークビジネスをしている。
My boyfriend does network marketing as a side job.
社員の副業をオッケーにするべきだという彼の提案は、一考に値する。
His suggestion that employees should be allowed to have a side job is worth considering.