attentive
unreflected
absent
absentminded
absorbed in
abstracted
bemused
buried
buried in
buried in thought
castle-building
caught up in
concentrating
contemplating
contemplative
daydreaming
daydreamy
deep
devoted
devoted to
dreaming
dreamy
drowsing
ecstatic
elsewhere
engaged
engaged in thought
engrossed
engrossed in
engrossed in thought
enmeshed in
entangled in
far-gone
faraway
half-awake
immersed
immersed in
immersed in thought
implicated in
in a reverie
in the clouds
intent
intent on
introspective
involved
involved in
lost
reabsorbed