Mout is likely misspelled.
Mout has no English definition.
As an acronym FIBUA
is fighting in built up areas
fibua
English
Acronym
(Acronym)
(head)
(military, British, Canada) fighting in built up areas mout
English
(Urban warfare)
Acronym
(Acronym)
(head)
(US, military) Military Operations in Urban Terrain, a term used to describe urban warfare.