Strikebreakers are people who are hired to work when the usual workers are on strike.
Some people think strikebreakers are good because they keep things working, but other people think they are bad because they take jobs from the usual workers.
Examples:
The company hired strikebreakers to keep the factory running during the strike.
The strikebreakers crossed the picket line to go to work.
The strikebreakers were not popular with the striking workers.
The strikebreakers were not very good at making friends with the striking workers.
The strikebreakers were like the new kids at school, but nobody wanted to play with them.
The strikebreakers felt a little scared when they saw the angry workers.