What does fastest mean?
Fastest is the superlative form of 'fast', functioning both as an adjective and as an adverb. As an adjective, it identifies the person, animal, machine, or thing that moves or is capable of moving at the greatest speed among those being compared — the fastest runner, the fastest train. As an adverb, it describes action performed with maximum speed or minimum duration, as in 'he finished fastest'. The word appears constantly in everyday speech and in fields where speed is measured precisely, including athletics, motorsport, computing, and engineering, giving rise to familiar phrases such as 'the fastest growing economy' and 'the world's fastest car'. Its connotations are almost entirely positive: speed suggests efficiency, ambition, progress, and excellence. Interestingly, 'fast' itself derives from an Old English sense meaning firmly fixed or secure, so the modern meaning of rapid movement evolved from a root about holding still.
Superlative of 'fast': moving, or able to move, at the greatest speed relative to others of its kind.
"The peregrine falcon is the fastest animal in the animal kingdom during its hunting dive."
Superlative of the adverb 'fast': performing or occurring an action with the greatest speed or in the shortest time.
"Of all the competitors, she recovered fastest after the interval."
The word 'fast' originally meant the exact opposite: it comes from an Old English verb meaning to be firmly fixed in place — so 'fastest' literally descends from a word about standing still.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of fastest
The adjective 'fast' traces back to Old English 'fæst', meaning firmly fixed, secure, or steadfast — a sense preserved today in words like 'steadfast' and in the verb 'fasten'. Over the medieval period, this meaning shifted remarkably: because someone who was 'held fast' could also be described as acting vigorously or without restraint, 'fast' came to mean rapid, producing the modern sense of high speed. 'Fastest' is simply the superlative inflection of that word, formed by adding '-est' following the standard Germanic pattern inherited from Old English. Cognate forms such as 'fasten' and 'fastness' survive from the same Germanic root.
Related word forms
How fastest is actually used
Fastest functions as both a comparative-grade adjective ('the fastest car') and an adverb ('she runs fastest'). Because 'fast' has no '-er/-est' alternatives like 'more fast', these forms are the only standard ways to express greater or greatest speed. Note that as an adverb grade, 'fastest' typically appears in post-position ('runs fastest'), not pre-position.
Easily confused with fastest
'First' means earliest in order or before all others in sequence, while 'fastest' means greatest in speed — a runner can finish first without being the fastest at any single moment.