preoccupied in WordNet English dictionary

1. deeply absorbed in thought
   "as distant and bemused as a professor listening to the prattling of his freshman class"; "lost in thought"; "a preoccupied frown"
   bemused  deep in thought  lost  preoccupied 
   
2. having or showing excessive or compulsive concern with something
   "became more and more haunted by the stupid riddle"; "was absolutely obsessed with the girl"; "got no help from his wife who was preoccupied with the children"; "he was taken up in worry for the old woman"
   haunted  obsessed  preoccupied  taken up