A suffix is a letter or a group of letters added to the end of a word. Using a suffix lets us make new words.
for example: tight + en = tighten
The suffix -en is used to change many adjectives (describing words) into verbs (doing or action words).
for example: sweet + en = sweeten
Mum's tea was not very sweet. (adjective)
She put sugar in it to sweeten it. (verb)
The suffix -ify can also be used to change adjectives into verbs.
for example: simple + ify = simplify (the 'e' is dropped before the suffix is added)
The sums were quite simple. (adjective)
I was struggling with my sums so my teacher simplified them for me. (verb)