There are several types of English constructions that get called "phrasal verbs". I can only speak authoritatively about my own usage of the term, and what I understand about others' usages.
I use the term phrasal verb specifically to cover what I originally learned to call "two-word verbs" (aka "Verb Plus Particle Construction") when I was teaching ESL in the 1960s. I learned then how troublesome they were to English learners; when we got to the chapter in our textbook about them, they would always insist I explain the meaning of each one, since they're so idiosyncratic.
(The link in the first sentence above goes to a freshman grammar homework problem about phrasal verbs in the sense I intend; the name of (one of) the rule(s) involved in the data is Particle Shift. 1p max)
I also learned how plentiful and variable phrasal verbs are in English, since my predecessor and mentor in that ESL job was George A. Meyer, who'd compiled a dictionary of them.
There are many more two-word verbs than one-word verbs in English, because just about every one-word verb appears in more than one two-word verb. And they're all idiomatic, though there are so many of them that many useful (but not completely reliable) patterns can be discerned.
There are also transitivizing prepositions, like the ones associated with the intransitive volitional sense verbs look and listen. It's usually desirable to indicate the focus of looking or listening, so the verbs' intransitivity is inconvenient.
English provides its usual sloppy syntactic solution --
- use a prepositional phrase to mark the object NP
- always use the same preposition
- never stress the preposition -- stress the object NP instead
- attach the preposition as tightly as possible to the verb in speech
- shift the boundaries to make [verb + preposition] a constituent
- treat the former prepositional object as the direct object of [verb + preposition]
The result is that look at and listen to are effectively transitive verbs. They are so transitive that they can be passivized.
- This has been looked at before, but nothing ever came of it.
- Will he really be listened to when he puts the proposal before them?
There is even an eye dialect spelling "lookit", as in Lookit that patina!. These constructions are also called "phrasal verbs" by some linguists in some contexts, and -- provided examples are given to nail down the phenomenon; data and context are crucial, always -- other linguists will understand what they mean. They differ from the first kind in that they don't undergo Particle Shift, and there is no semantic content to the preposition, even though it is cliticized to the verb like the first type.
There are others, too. But this is already too long.