To preoccupy the mind of excessively.
To have the mind excessively preoccupied with a single emotion or topic: "She's dead. And you're still obsessing” ( Scott Turow).
To preoccupy completely; haunt
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
To worry neurotically or obsessively; brood
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