attrition

1 ENTRIES FOUND:
attrition /əˈtrɪʃən/ noun
attrition
/əˈtrɪʃən/
noun
Britannica Dictionary definition of ATTRITION
[noncount] formal
1 
chiefly US : a reduction in the number of employees or participants that occurs when people leave because they resign, retire, etc., and are not replaced
— called also (British) natural wastage
2 
: the act or process of weakening and gradually defeating an enemy through constant attacks and continued pressure over a long period of time — used especially in the phrase war of attrition