Dejar an intransitive verb?
For the grammarian in me would you all be able to post examples of stopping using dejar?
In the course of my studies, I've been discovering stop as in alto the interjection, parar the verb and now dejar the intransitive verb. Unfortunately, I lost my original sentence but under item 11 in our translator, I found dejar the intransitive verb. I googled "intransitive verb" and found out that it is a verb that expresses action without a direct object.
dejar de hacer algo -> to stop doing something
ha dejado de fumar -> he stopped smoking
I found the about.com link on intransitive Spanish verbs
But now I look at the spanishdict translation and I wonder if I'm understanding intransitive. Aren't "doing something" and "smoking" in the above examples direct objects of stopped?
5 Answers
A verb does not necessarily have to be either transitive or intransitive. Many verbs can be used with transitive or intransitive constructions:
Andar por la calle (intransitive construction) Andar el camino (transitive construction)
Regarding "dejar", look at these examples:
1) Deja las llaves (transitive construction, "las llaves" is the direct object) 2) Deja de molestarme
The second construction is called a periphrasis in Spanish grammars. English has some of these periphrases as well: "I am going to think", "I will call",... While the verb "dejar" is used intransitively, it actually joins "molestar" to create a more complex and indivisible structure (a periphrasis) that works like a single verb would. Thus, "dejar de molestar" is actually a transitive construction.
The grammarian in me has been slumbering for decades, so I'm not going to touch the finer points of this question. I would like to contribute that dejar always implied some form of release to me- "dejalo suelto", (let or leave him loose) "dejalo solo" (let or leave him alone) "Dejar de fumar" could imply letting go of the habit, or dropping it. That doesn't address the main point of your question though, so I guess I should do as I told myself to; Post less and read more so I can maybe learn something.
dejar de hacer algo -> to stop doing something
ha dejado de fumar -> he stopped smoking
Intransitive in Spanish but your English translations use transitive verbs to communicate the same idea.
Note: you cannot say "Dejar fumar" (as though the verbal noun 'fumar" were the direct object of "dejar") . The same with "Dejar hacer*." (it doesn't work)
In English "He stopped smoking." is transitive construction. "smoking" is a gerund and is the direct object of "stopped". (cf "He stopped the car.") Aside: "to stop" can also be used intransitively (e.g. "I'll stop when I come to a red light.")
The fact that "to stop" is a good translation of "dejar", has to do with the similarity of meaning. It does not necessarily mean that the grammatical usage will be the same in both languages.
Good question, is it because it can be both transitive and intransitive?
The object that directly receives the action of the verb is called the direct object.
so (and this is just a guess)
He stopped smoking. - would be using it intransitively
but
He stopped smoking cigarettes - gives it a direct object, answering who or what receives the object of the action - stopping smoking.
I'm probably way off tho' and will look forward to reading the answer of someone who really knows what they're talking about lol 
Thanks everybody for the great information. I was hoping to see some kind of grammatical clue to indicate the meaning of dejar in a sentence. I guess it is just something I have to learn over time. 
