detachment

Short definition from Wiktionary

Noun

1. 1
   The action of detaching; separation.
2. 2
   The state of being detached or disconnected; insulation.
3. 3
   Indifference to the concerns of others; disregard; nonchalance; aloofness.
4. 4
   Absence of bias; impartiality; objectivity.
5. 5
   The separation of a military unit from the main body for a particular purpose or special mission.
6. 6
   The unit so dispatched.
7. 7
   A permanent unit organized for special duties.
8. 8
   Any smaller portion of a main body separately employed.