Augmentative Suffixes - azo
Well I learnt something very interesting today, thanks to Maestro JC - did you know that the augmentative suffix -azo indicates a blow or a strike?
-Azo to indicate a blow or strike: The suffix -azo can be applied somewhat freely to nouns to indicate a blow or strike; coined words using this suffix are sometimes found in journalese. Words formed in this way are always masculine.
Examples: hachazo (blow or chop with an ax), martillazo (blow with a hammer), puñetazo (punch with a fist), cabezazo (head butt), codazo (jab with the elbow), plumazo (the stroke of a pen), huevazo (a blow from a thrown egg), misilazo (missile strike), sartenazo (a blow from a frying pan)
So what is meant by 'abrazo'? 
13 Answers
"Abrazo" does not use the suffix -azo. It is the noun from the verb "abrazar", from "brazo". It is like
cantar -> un canto
abrazar -> un abrazo
While it can be used sometimes as an augmentative suffix (used with good or bad intentions), it is also used as a pejorative one, and both as augmentative and pejorative at the same time, often depending on the context and the intention of the speaker, as in "perrazo", which can be a huge dog, if you are commenting on the size, a dog you despise, if you are making bad comments about it, or both.
"Manaza" and "bocaza" are examples of pejorative references to parts of the body. Interestingly, this suffix it is very often used for big or great things in a positive way, as in "partidazo", "cuerpazo", "besazo" or "madraza".
It is also a very productive suffix for hits, strikes and sudden collisions or energetic encounters. The number of words in this group is quite large, and you can easily create your own words: arañazo, balazo, bastonazo, botellazo, cantazo, culatazo, escobazo, espaldarazo, estacazo, lametazo, martillazo, palazo, pelotazo, portazo, porrazo, puñetazo,... A thread on creating words like this could be quite funny and creative. An example: "Le dio un jamonazo al vehículo".
cacerolazo - Banging on pots and pans as a form of protest. (Thanks KevinB)
You might want to review this short article on -azo suffix.
This suffix is used in three ways:
1.Forming augmentatives; words expressing greatness or size
2.Forming pejoratives; words emphasizing contempt for a subject
3.Forming words expressing a hit or strike
The second category is interesting enough, but I don't want to quote examples here 
Pelo - hair : Pelazo - great luscious hair
Puerto Ricans have a number of very colorful expressions that are not found anywhere else in the Spanish-speaking world, as far as I know.
They use "guayazo" for example, to mean a scratch. In other places this might be called "un rayón. "
A man that was doing some work in our house let us know that he had received an electrical shock by telling us that: "el cable me dió un cantazo".
In other places, en electrical shock would be "un corrientazo."
madraza - It's not quite the azo suffix, being naturally feminine, but it seems to fit this thread:
madraza
feminine noun
1.= indulgent or doting mother
augmentative
2.= A very fond mother. (f)
Interesting!
How about "pedazo," which means a piece of something. I wonder how that relates.
I found this great one:
flechazo - arrow shot / arrow wound, or figuratively "love at first sight"
Example: le ha dado el flechazo = he's smitten
It could have that meaning orginally, but has come to simply a hug or embrace.
From your list of examples I will choose plumazo (the stroke of a pen).Thus abrazo must be the stroke of an arm.
I choose portazo - slam of a door.
Bueno, me gusta mucho la lengua coloquial, entonces voy a poner este ejemplo: "Qué coñazo de este libro."
"What a boring book".
Creo que el origen de esta palabra es fácil de adivinar, ¿no?
Well it looks like Diego Torres agrees with Margaret, so palmada is winning so far 
La Flor Más Bella "Y una palmada se oyó el canto de una sirena"
