affixes

An affix is a group of letters added to the beginning or end of a word to change its meaning.

A prefix is an affix that is added to the beginning of a word.

The prefix 'un-' means 'not'. For example, 'unhappy' means 'not happy'.

The prefix 'dis-' means 'not' or 'opposite of'. For example, 'disagree' means 'not agree'.

The prefix 'pre-' means 'before'. For example, 'preview' means 'to see before'.

The prefix 'post-' means 'after'. For example, 'postpone' means 'to put off until after'.

The prefix 'extra-' means 'beyond' or 'more than'. For example, 'extraordinary' means 'beyond ordinary'.

The prefix 'in-' can mean 'not' or 'into'. For example, 'incomplete' means 'not complete'.

The prefix 'over-' means 'too much' or 'excessively'. For example, 'overeat' means 'to eat too much'.

The prefix 'under-' means 'too little' or 'below'. For example, 'underestimate' means 'to estimate too little'.