Fatigue
Weariness
noun, verbal noun
You're tired from labor. From this, you're showing fatigue and weariness.
疲労 is a little formal, so you might encounter it more often in writing than in conversation.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
仕事のストレスのせいで疲労がたまっているんです。
I have a lot of accumulated fatigue because of stress from work.
このクツ、すごくいいよ！ディズニーランドで一日歩いたのに、足に疲労が出なくてビビったぐらい。
These shoes are great! I even walked all day at Disneyland and was shocked that my feet didn't get fatigued.
このエナジードリンクを飲めば疲労が一発でとれるんです。
If you drink this energy drink, you can get rid of fatigue right away.