This is the 528th most frequent Czech word.
mladší
Younger.
The adjective 'mladší' is used here in its comparative form to compare the ages of two individuals.
Můj bratr je mladší než já.
My brother is younger than me.
The adjective 'mladší' is used to indicate a familial relationship, describing a sibling who is of a younger age relative to the speaker.
V naší rodině mám mladší sestru a staršího bratra.
In my family, I have a younger sister and an older brother.
The adjective 'mladší' is used metaphorically to describe a more recent or newer object, in this case, a car.