preocupar
transitive verb
1. to worry (inquietar)
me preocupa no saber nada de él -> I'm worried I haven't heard from him
2. to bother (importar)
sólo le preocupa su apariencia externa -> he's only bothered about his appearance
preocuparse
pronomial verb
1. to worry (inquietarse) (por about), to be worried (por about)
no te preocupes -> don't worry
no te preocupes por ella -> don't worry about her
2. (encargarse)
preocuparse de algo -> to take care of something
preocuparse de hacer algo -> to see to it that something is done
preocuparse de que… -> to make sure that…