Difference between "commit suicide" and "suicide"

Solution 1:

There is no difference semantically. The only difference is that "suicide" as a verb is so rare I have never seen it before; whereas "commit suicide" is common. I would advise against unusual usages in general: You might confuse people, which is ill-advised, and in this case it is totally non-constructive to the language.

Solution 2:

Both the NOAD and the OED (the electronic version available on my Mac) reports that suicide is also a verb, and it means "intentionally kill oneself."
The example given by both the dictionaries is the following:

She suicided in a very ugly manner.

This meaning of suicide is not reported to be literary, archaic, or poetic.

The same dictionaries report that commit in commit suicide means "carry out or perpetrate (a mistake, crime, or immoral act)."

He committed an uncharacteristic error.

Solution 3:

While there is no difference between "to commit suicide" and "to suicide" ^[1]. Note that "suicide" can also be used to refer to the subject of the suicide. So while you can say "He committed suicide" you could also say "He is a suicide".

([1] Although I would always use the first as it is, as has been said, far more common. )

As to why it is "committed" and not something else, I suspect it's one of two reasons.

The word, committed, has a finality associated with it. If you commit to something, you are making a pledge to do that thing and not go back on your pledge. Or, you may commit something to memory; the thought being that rather than it being a passing thing you have remembered, it is there for the long term.

Either that, or perhaps it is that "commited" is also often used in place of "perpetrated" in regard to crime. And until very recently (the 60's I think) in the U.K at least, suicide or attempted suicide was considered a crime. (Whether this was/is true in other parts of the world I don't know.)

Solution 4:

I think the difference between suicide and other verbs is that suicide used to be a crime, and so has the same form as other crimes or things that used to be crimes.

Commit has the meaning to perpetrate, so any verb that is/was a crime, can be committed.

In this sense, suicide is not being used as a verb, but a gerund.

So, you can commit