The word "luck" can be used as a noun or as an adjective. If a person has luck, he or she has good or bad fortune. Luck is something that can’t be planned. It comes spontaneously.
Joan and Bill have a lot of luck. They just won the lottery.
With a little luck, Dave will find a new job.
Nellie counted too heavily on luck when planning her future.
Do you believe in luck?
The word "lucky." is an adjective.
They’re very lucky to have found each other.
I’m hoping to get a lucky break with some good weather today.
You’ll be able to get tickets to that concert if you’re lucky.
Helen says she’s feeling lucky today, so she bought some lottery tickets.
John’s car broke down on the highway. Luckily, someone pulled up a few minutes later and helped him fix it. (The word "luckily" is an adverb.)
There are some expressions that use "luck" or "lucky."
He’s a little down on his luck. (Things are not going well for him.)
She’s a lucky duck. (She has a lot of luck.)
This is your lucky day. (There’s good news for you.)
Of all the luck. (Something bad happened.)
They’ve run out of luck. (They were lucky, but now they aren’t.)
You’re out of luck. (You can’t have what you asked for.)
The luck of the Irish. ("Luck" is often associated with being Irish and Irish culture.)