engage or engross the interest or attention of beforehand or occupy urgently or obsessively; "His work preoccupies him"; "The matter preoccupies her completely--she cannot think of anything else"
occupy or take possession of beforehand or before another or appropriate for use in advance; "the army preoccupied the hills"
intelligence activities concerned with identifying and counteracting the threat to security posed by hostile intelligence organizations or by individuals engaged in espionage or sabotage or subversion or terrorism