What is a suffix?

Note the following word groups:

Wall - seawall

voice – little voice

ox - herd

cruel - cruelty

head - head

weak - weakly

Note that the words in red, formed after adding units (-ah, -inha, -ada, -dade, -ear, -mind) to the radical from the previous word, are new words that present an idea different from the original in another grammatical category. This minimum significant unit that integrates the word is given the name of suffix.

Thus, it can be said that the suffix is ​​the element that is added after the stem to modify its meaning. It can be classified as nominal, verbal and adverbial.

nominal suffix

It's the one that joins the radical to give rise to a substantive or to a adjective.

See some examples:

augmentative suffix	-alloon	grandgarlic
diminutive suffix	-ino	smallino
Suffix that forms noun from another noun	-ada	paperada
Suffix that forms noun from adjective	-(i) give	freebig boy
Suffix that forms noun from noun and adjective	-ism	realism heroism
Suffix that forms noun and adjective from another noun and adjective	-ist	realhey toothhey
Suffix that forms noun from verb	-hip	rememberhip
Suffix that forms adjective from noun	-steel	manisteel
Suffix that forms adjective from verbs	-before	toleratebefore

verb suffix

It's the one that joins the radical to give rise to a verb.
See some examples:

-ear	leafear
-eja	gotejar
-enter	sourenter
-(i) stay	dignifiedcertify
-stay	drinkstay
-island	fingerisland
-bath	wroteswell
-stare	saltitate
-ize	civilgo

adverbial suffix

In Portuguese, there is only one adverbial suffix, -mind, which joins the feminine form of an adjective to form a adverb.

See some examples:

-mind

Francemind kind-heartedmind slowmind weakmind

By Mariana Rigonatto
Graduated in Letters

Source: Brazil School - https://brasilescola.uol.com.br/o-que-e/portugues/o-que-e-sufixo.htm