The meaning and origin of the expression: Fast asleep

Fast asleep

What's the origin of the phrase 'Fast asleep'?

There might seem to be little need to explain the term 'fast asleep', as it is a basic everyday expression that few of us would give much thought to. But, giving it some thought, we might also ask, why 'fast' and also, why 'asleep' rather than 'sleeping'?

The common meaning of fast is now 'speedy', 'rapid', which clearly has little to do with sleeping. The 'fast' in 'fast asleep' derives from the Old German 'fest', meaning 'stuck firmly'; 'not easily movable' - as in 'stuck fast'.

'Asleep' derives from 'sleep' in the same way that nautical adverbs like 'aground' and 'astern' derive from 'ground' and 'stern'. To be 'fast asleep' was to be stuck firmly in sleep, analogous to a beached ship being 'fast aground'.

'Fast asleep' is found in numerous texts from the 15th and 16th centuries. The earliest example that I can find is in John Gower's Confessio Amantis. This book was published in 1483 or, as the publisher put it:

"Enprynted at Westmestre by me Willyam Caxton, and fynysshed [in] the fyrst yere of the regne of Kyng Richard the thyrd", [i.e. 1483]. Gower died in or about 1408 so we can assume that the text dates from the very early 15th century.

Gower used 'fast asleep' several times in the book, for example:

When that the pope was fast a slepe.
That euery man was fast a slepe.
And whyle the lord is fast a slepe.
and so...

Many early citations interchange 'fast asleep' with 'in a fast sleep'. Notable of these was William Shakespeare, who used that term to describe Lady Macbeth's nocturnal ramblings, in Macbeth, 1605:

Since his majesty went into the field, I have seen her rise from her bed, throw her night-gown upon her, unlock her closet, take forth paper, fold it, write upon't, read it, afterwards seal it, and again return to bed; yet all this while in a most fast sleep.

See also: sleep like a top.