When we come across a word we don’t know, we can often work out what it means by knowing what the prefix or suffix means.

We know, without having to think about it, that the prefix un turns a positive into a negative. Happy becomes unhappy, done becomes undone. Dis means ‘the opposite of’ or ‘not’, as in disconnect or disease (the opposite of ‘ease’). De also implies reversing a verb’s action, such as defrost or deregulate.

Mis means ‘wrong’, such as mistreat or misprint, trans is ‘across’ ie transport from trans + portare ‘carry’, and anti is ‘against’ or ‘opposite’ eg anticlimax.

Pre often means ‘before’ such as prearrange or prepaid. The word predict, meaning ‘foretell’, comes from prae ‘before’ + dicere ‘to say’.

Post means ‘after’, as in postdate, postmortem or postscript. The word preposterous originates from both of these additions, prae ‘before’ and posterus ‘subsequent’, literally ‘before-behind’ or ‘contrary to nature, absurd’.

Re means ‘again’ such as reread or reshape, and over implies too much of something, overconfident, overcharge etc.

Common suffixes are able or ible meaning ‘can be done’, such as audible or reliable. Er can either be a comparative, eg higher, calmer, or the doer of a verb, such as teacher, learner.

However, being our wildly irregular English language, you can’t rely on any of these meanings because some words can’t be analysed thus. There are alternatives and exceptions to nearly every one of these prefixes and suffixes.

While in and ex are often opposites, such as include/exclude, or introvert/extrovert, this is not the case with incite/excite or intend/extend. Repose is not ‘to pose again’ and devote does not mean ‘undo vote’.

Over as a prefix can also mean ‘above’, ‘completely’ or ‘outer’ such as overarm, overjoyed and overcoat, which do not imply excess.

Telethon is another word like preposterous, made from tele ‘at a distance’ and thon denoting prolonged activity without a root word.

The original Latin or Greek meanings have often changed over the centuries or acquired alternative meanings.

What a strange and difficult language English must be, to those who didn’t learn at their mother’s knee.

Happy Puzzling!