Let's say you watched a war-related movie, wherein the bomb was dropping down a city. And then, you storytell it to your interested friend.

Oh man, the movie was so intense! The aircraft dropped the bomb too fast!/ too fastly!

I think I've heard or read the usage of too fast similar to my example, and this is ungrammatical(I think) that even natives say that.

So is this an exception to the grammar rules now?

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    Ah! Did you mean to say "the bomb was dropped too soon", or "the bomb was dropped too early"? Also, an aircraft does not drop a bomb, it carries a bomb, and a crew member or machine decides when to drop it. But the bomb, once released, always falls at the same speed, so it cannot be "too fast", and definitely not too fastly because fastly is not a word. Jul 15, 2018 at 20:42
  • @WeatherVane, thx for the info. about the function of aircrafts, but seriously, do I really have to be so literal about it? Can it be understood if I just use aircraft dropping the bomb and not a crew or a pilot?
    – John Arvin
    Jul 15, 2018 at 21:37
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    Agree with Weather Vane. When a plane drops a bomb, it falls at the speed decided by gravity. It can't fall 'too fast'. Jul 15, 2018 at 21:38
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    When a bomb falls out of a plane, it doesn't "fall at the same speed" during all of its journey to the ground. It is accelerated by gravity to a terminal velocity. Sep 5, 2018 at 21:51

1 Answer 1


Many adverbs end in -ly, but not all of them do. Fast can be an adjective, but in this case fast is an adverb, and there's nothing non-standard or ungrammatical about it. Fastly, on the other hand, would be ungrammatical; fast is already an adverb, and there's no need to add -ly.

Dictionaries aren't always right about parts of speech, but in this case they'll give you the right answer. Macmillan Dictionary, for example, defines fast as an adverb which means 'quickly'. As you've noticed yourself, this usage is quite common.

Too fast isn't especially informal, but in formal speech it might be better to say too quickly instead.

  • I think you get my point. In a nutshell, the word fast is a unique one huh, it can be an adverb too(I already know it is an adjective, that is why I'm learning what is the adverb of it)
    – John Arvin
    Jul 15, 2018 at 21:34
  • @JohnArvin an interesting question, since we say "slow" and "fast"; "slowly" but not "fastly". Jul 15, 2018 at 22:53
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    @JohnArvin It's actually not unique, but there aren't a whole lot of flat adverbs in Standard English. One flat adverb learners have to be particularly careful of is hard. Hard can be an adjective or an adverb, while hardly is a different word with a different meaning, not the adverb form of hard. It's important not to mix them up.
    – user230
    Jul 15, 2018 at 22:57

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