A suffix is an affix that follows the morphemes to which it can attach. In plain English, it's a small addition at the end of a word(or part of word). An example from colloquial (British) English would be the word "soonish", where the "ish" modifies the "soon", meaning "soon, but not all that soon".

''See List of English suffixes, for suffixes used in English. These are typically of Greek and Latin origin.

Suffix | Sufijo | Sufikso | Suffixe | Suffix | Suffix | Suffix | suffix