a busy life.
a busy man.
a busy painting.
a busy seaport.
a busy street.
a fussy design.
a very busy week.
an interfering old woman.
bustling about self-importantly making an officious nuisance of himself.
busy about other people's business.
busy with her work.
her line is busy.
kept getting a busy signal.
receptionists' telephones are always engaged.
She busies herself with her butterfly collection.
the lavatory is in use.
too busy to eat lunch.