One of the most common prefixes used in Spanish is a. This prefix is very interesting because when coming from the Latin prefix ab- or abs-, a- denotes separation or privation, but when coming from the Latin prefix ad-, a- denotes approximation or presence. Another interesting and useful aspect of this prefix is that it can be added to certain nouns and adjectives to form verbs.
Let's compare the different uses of the prefix a-. Take the word ausente (absent). This is a perfect example of the use of the prefix a- to indicate separation. We have a full movie titled El Ausente:
Ya llegó el que andaba ausente y éste no consiente nada...
Now he arrived, the one who was absent and this one does not allow anything...
Caption 6, El Ausente - Acto 3 - Part 5
Strikingly enough, the prefix a- can also mean approximation or presence. A good example is the verb asistir meaning "to attend":
Siempre hemos de asistir personalmente a la entidad bancaria.
We should always go personally to the banking entity.
Caption 13, Raquel - Abrir una cuenta bancaria
Much more practically useful is to know that we can add the prefix a- to other words, like nouns and adjectives, to form verbs. Below is an example from a video published this week. The verb acostumbrar (to get used to) is formed with the prefix a and the noun costumbre (custom, use):
Vea, Pepino, hay sitios donde les enseñan a los animales a que se vuelvan acostumbrar a su hábitat.
Look, Pepino [Cucumber], there are places where they teach animals to get used to their habitat again.
Caption 9, Kikirikí - Animales - Part 7
Now, using the noun tormento (torment) we get the verb atormentar (to torment):
Eso seguro era algo que podía atormentarlos.
That surely was something that could torment them.
Caption 43, Sub30 - Familias - Part 10
There are so many! From susto (fright) you get asustar (to scare):
¡Ay no, Candelario! No me asustes.
Oh no, Candelario! Don't scare me.
Caption 38, Guillermina y Candelario - La Isla de las Serpientes - Part 1
You can also use adjectives. For example, lejos (far) and cerca (close) give us alejar (to put or to go far away), and acercar (to put or to get close):
Después me alejaré
Then I will go away
Caption 21, Reyli - Qué nos pasó
Ella trataba de acercarse a mí.
She tried to get close to me.
Caption 9, Biografía - Pablo Echarri - Part 3
Here is a list with more examples. Maybe you can find them in our Spanish catalog.
Tonto (fool) - atontar (to fool or become a fool)
Plano (flat) - aplanar (to flatten)
Grande (big) - agrandar (to make bigger)
Pasión (passion) - apasionar (to become passionate)
Nido (nest) - anidar (to form a nest)
Morado (purple) - amoratar (to get or give bruises)
Francés (French) - afrancesar (to become French-like)
Grieta (crack) - agrietar (to crack)