Whole Body, Entire Body
noun, の adjective
The all of somebody is someone's whole body.
ぜんしん
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
一日に一回、全身にスプレーして下さい。
Please spray over your whole body once a day.
毎日、全身ビジネススーツで会社に行きます。
Every day, I go to work in a business suit from head to toe.
カニのアレルギーで全身にたくさんの赤い点が出てしまった。
I had a lot of red dots throughout my body due to a crab allergy.