preoccupied

(s) 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,
(s) 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, taken up,

bemused deep in thought lost haunted obsessed taken up