Answer: obsessive

AnswerCrossword Clue
OBSESSIVESingle-minded to a degree.
OBSESSIVEAbnormally preoccupied
OBSESSIVEMonomaniacal
OBSESSIVESingle-minded
OBSESSIVELike Ahab's pursuit of Moby Dick
obsessiveOf the nature of an obsession
obsessivesubject to obsession / someone affected or characterized by obsessive behaviour
obsessiveAffected by an obsession