What's the difference between 補給, 補充, 補足, 補完?


According to Denshi Jisho, they mean "supplementation" but I wonder if there
is any difference in their nuances.

Here are some examples where they are used:

  1. 小まめに **補給** することが大切です。
  2. 職員の欠員を **補充** するために広告を出した。
  3. この件について **補足** の説明をさせてください。
  4. 学校での教育を **補完** する役割が塾にはある。




They're quite different words. Grammatically, all of them are used as verbs
with `～する`.

**`補充`** is better translated as _to replenish_ , that is to refill something
when the number/amount of them have decreased.

**`補給`** is a special case of `補充`, whose replenishment is intended for
immediate consumption. Typical ones I imagine are water for marathon runners,
and ammo for front-line soldiers. You can use `補充` instead of `補給`, but not
necessarily vice versa.

If `補給` is used without object, it's usually considered as _to take
nourishment_.

**`補足`** is _to add words as afterthoughts_. You can only use it for adding
information.

**`補完`** is _to complement with something obverse_.

* * *

**Supplementation on krnk's comment:**  
`補填` is _to make good a deficit_ , and `補償` is _to compensate (for a damage)_.

