Pronominal verbs

Pronominal verbs, often (misleadingly) called reflexive verbs, are verbs in which a "pronoun" clitic is inserted that agrees with the subject. The term reflexive is often used to cover all these verbs, because a helpful notion for understanding them is that "the object of the verb is the same thing/person as the subject", as in English he washed himself. However, there are cases such as reírse where this analysis is less clear. So strictly speaking, reflexive verbs can be seen as a subset of pronominal verbs.

The infinitive of pronominal verbs has the clitic se added to the end: lavarse, bañarse, esconderse, hartarse etc.

Example

Here is the verb bañarse, to have a bath/shower, conjugated in the present tense:

Note that the clitic "agrees" with the subject, even though that subject may not actually be expressed. For example, in me baño, the clitic me (=myself) "agrees with" the subject yo, although this subject isn't explicitly expressed.

Word order

With pronominal verbs, the clitic follos the word placement rules of clitics in general. In continuous forms, the clitic can be attached to the participle (ending in -ando/-endo) or come before the form of estar. So either se está bañando or está bañándose is possible. In compound tenses such as the perfect, placing the clitic before the form of haber is more common (me he bañado rather than ?he bañádome).

Types of pronominal verb

Pronominal verbs fall into various categories:

reflexive verbs

Verbs where the clitic obviously "references" the subject (i.e. has a -self meaning), even if it isn't always translated as such in English. For example, the Spanish verb lavarse is usually translated as to wash or to have a wash, but there is an obvious literal meaning of "to wash oneself"¹.

emphatic reflexive verbs

Many verbs can be made reflexive for emphasis, giving an effect similar to he went and... or if you please in English. With verbs of eating/drinking, the effect is similar to putting up after the verb: se lo comió = he ate it up; se lo robó = he went and stole it.

reciprocal pronominals

Pronominal verbs can also have a reciprocal ("each other") meaning. So se han visto would generally mean they've seen each other.

passive pronominals

There isn't a sense of the subject performing an action to itself. Instead, the pronominal construction can be seen as a type of "passive without an agent". For example: la situación se ha convertido en un drama the situation has turned into a drama.

intrinsically pronominal verbs

There are a few cases such as the verb antojarse, or the construction reírse (de algo), where in simple terms, the verb is pronominal "just because it is". It's difficult to break the verb down and say that the clitic has a particular "unit of meaning" such as being reflexive, reciprocal or passive.

1. These verbs can often be identified (at least by native Spanish speakers!) by seeing if it's possible to paraphrase them with a construction involving a sí mismo. For example, se lavó could be (emphatically) paraphrased as se lavó a sí mismo.