Wiktionary
a. (context informal English) Very tired, or exhausted due to hard work or physical exercise.
Usage examples of "fagged out".
But he was one of your wrath-of-God tyrants who won't be gainsaid, and quoted Queen's Regulations, and bullied me about Duty and Honour - and I was young then, and fagged out with tupping Ranavalona, and easily cowed.
The Tremain kid was young, strong as a bull, but he had fagged out in two days.
I celebrated with a quart of your vile porter and a bolus, and turned in at once, quite fagged out.
I was fagged out, and for the first time in years felt a question as to my ability to cope with an antagonist.
I shall not play well, being quite fagged out, as our American captive says.
I write now though I am utterly fagged out, because writing to you rests me.