Meaning: Tangled hair, (as if matted my sly little elves who come into your bed at night)
As in: Look at the state of those elflocks — has that guy ever heard of a comb?
What would Shakespeare say (WWSS) about all this?
Here’s a reference from Mercutio’s speech in Romeo and Juliet on the exploits of Queen Mab, where he seems to imply the locks are only unlucky if combed out:
“She is the fairies’ midwife, and she comes
In shape no bigger than an agate stone…….
That plaits the manes of horses in the night
And bakes the elflocks in foul sluttish hairs
Which once untangled, much misfortune bodes.”
According to Shakespeare then, an ‘elf lock’ or ‘fairy lock’ could be attributed to any various tangles and knots of unknown origins appearing in the manes of beasts or hair of sleeping children. Also, in King Lear, when Edgar impersonates a madman, “he elfs all his hair in knots.” (Lear, ii. 3.) – i.e. he messes up his hair.
Shakespeare here also teaches us that hairs can be ‘sluttish’ (see above). Worth remembering next time you brush.