fair-weather friend
Plural
fair-weather friends
1
a person who is only a friend during good times and is not supportive or reliable during difficult or challenging times
The idiom "fair-weather friend" is derived from the fact that a fair-weather day is a day when the weather is mild and pleasant. Similarly, a fair-weather friend is someone who is only around when things are going well. It is used to describe someone who appears to be a friend but abandons or turns against you when you face hardships or adversity. It highlights the insincerity or lack of true friendship.
- Lisa claimed to be my friend, but she disappeared when I needed her the most.She turned out to be a fair-weather friend.
- Whenever I have a problem, John suddenly becomes unavailable.He's proven himself to be a fair-weather friend time and again.