Once in a while I see phrases like "Think" is not a four-letter word and just about any word can be where "think" is.

I looked up the Wikipedia and looks like it says that "four-letter word" means slang words with mostly negative meaning.

What does "four-letter word" mean here? Does it mean something like "it's not that bad to think once in a while"?

  • This should be obvious, but it is a pun. As other people have already explained, “four-letter word” in this context means something to avoid. At the same time, “think” consists of five letters, not four. Nov 17, 2010 at 18:36
  • [Insert four letter word here.] Mar 7, 2011 at 7:52
  • a four-letter word is an unabbreviated form of f**k
    – Pacerier
    Jul 29, 2011 at 13:40

4 Answers 4


Idiomatically a four-letter word is a swearword, considered rude and unacceptable in certain contexts.

The implication is here is that thinking and coming up with original solutions to problems is not to be frowned upon in the same way, and indeed is acceptable and encouraged.


It simply means "[X] is not a swear word."

The implication is that you have been avoiding [X], and the speaker is assigning a (highly unlikely, as the speaker is well aware) cause to that avoidance. As such, it's a form of hyperbole.


The phrase "four-letter word" is used to refer to one of the many offensive slang words in the English language containing four letters.

Usually the word fuck is intended or implied but there are many others, as listed by Wikipedia in your link. Again, from your Wikipedia link we learn that other languages have a similar term, sometimes referring to three or five letters depending on the language and its key swear words.

To say something is not a four-letter word is often used humorously or to provoke thought, since the author is suggesting that the something should not be considered especially bad. Often the something isn't commonly thought to be bad at all, hence the mild humour.

  • 5
    It's funnier when the word is in fact spelled with four letters, though. Like, say, goto.
    – SamB
    Feb 11, 2011 at 5:48
  • 3
    @SamB XKCD Mar 7, 2011 at 7:53
  • 1
    @SamB: Using goto in computer programming is considered bad practice (and in modern programming languages well hidden or not possible). So this would by many programmers actually fall into the category of four letter word also in the meaning of being a swear word...
    – awe
    Jan 25, 2013 at 9:14

There is a popular song by the band Cake called Friend Is a Four Letter Word on their album Fashion Nugget.


 But to me, coming from you,
"Friend" is a four-letter word,
"End" is the only part of the word
 That I heard...
 Call me morbid, or absurd,

 But to me, coming from you,
"Friend" is a four-letter word.

(Mostly unrelated, but as the question has already been answered I thought it was an interesting example)

  • I also thought of the same song; the implied “let's stay friends from now on” that the other party has said clears a little the “But to me, coming from you, "friend" is a four-letter word”. Feb 14, 2011 at 13:19
  • @TZ: I don't exactly understand your comment.
    – sova
    Feb 15, 2011 at 1:54
  • As you say, this is mostly unrelated and would be better as a comment. Sep 10, 2012 at 14:18

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