Webster's Revised Unabridged Dictionary · 1913

Fag

Fag (fag) , noun

1.
A knot or coarse part in cloth; a flaw. [Obsolete]
2.
A cigarette. [slang]
3.
A fag end in a cloth.
4.
A drudge.

fag (fag) , noun

A male homosexual; -- always used disparagingly and considered offensive. Shortened form of faggot. [Slang, disparaging.]

Fag (fagd) , intransitive verb

[Compare LG. fakk wearied, weary, vaak slumber, drowsiness, OFries. fai, equiv. to fāch devoted to death, Old Saxon fēgi, Old High German feigi, German feig, feige, cowardly, Icelandic feigr fated to die, Anglo-Saxon fage, Scot. faik, to fail, stop, lower the price; or perh. the same word as English flag to droop.]

1.
To become weary; to tire.
Creighton withheld his force till the Italian began to fag. — G. Mackenzie
2.
To labor to wearness; to work hard; to drudge.
Read, fag, and subdue this chapter. — Coleridge
3.
To act as a fag, or perform menial services or drudgery, for another, as in some English schools.
Collocations (1)
To fag out , to become untwisted or frayed, as the end of a rope, or the edge of canvas.

Fag , transitive verb

1.
To tire by labor; to exhaust; as, he was almost fagged out.
2.
Anything that fatigues. [Rare]
It is such a fag, I came back tired to death. — Miss Austen
Collocations (1)
Brain fag (Medicine) , See Cerebropathy.