A suffix is a letter or group of letters added to the end of a word. Knowing what a suffix means can help us understand new words.
For example, the suffix -able means 'able to' or 'capable of'.
Clothes that are able to be washed are washable.
A mattress that can be inflated is inflatable.
If the word ends in -e then we drop the -e before we add the suffix.
value / valuable
use / usable
If the word ends in -y then we usually change it to 'i' before we add the suffix.
deny / deniable
magnify / magnifiable