As in many other languages, Irish adds prefixes to words to create new words. If you become familiar with the prefixes below, you may double your [vocabulary]! Note that some prefixes are separated from the base word by a [hyphen], and some prefixes cause lenition.

ain-   in-, un-, not-, over-
Examples: ceart (right) becomes aincheart (unjust), fios (knowledge) becomes ainfhiosracht (over-curious).
an-   very
Example: maith (good) becomes an-mhaith (very good).
ath-   re-
Example: déan (do, make) becomes athdéan (redo, remake).
ceann-   chief, main, -headed
Example: litir (letter) becomes ceannlitir (capital letter).
comh-   mutual, joint
Example: ceol (music) becomes comhcheol (harmony).
dea-   good, well
Example: scéal (news, story) becomes dea-scéal (piece of good news).
dearg-   red-, real, utter
Example: gráin (hatred) becomes dearg-ghráin (intense hatred).
dé-   bi-, di-, two-
Example: taobh (side) becomes déthaobhach (bilateral).
di-   de-, dis-, in-, un-
Example: scéal (news, story) becomes díscéil (uninformative).
do-   in-, un-, not-
Example: déanta (done, complete) becomes dodhéanta (impossible, hard to do),
il-   many, multi-
Example: eochair (key) becomes ileochair (master key).
in-   capable of
Example: creidte (believed) becomes inchreidte (believable).
lán-   total
Example: cead (permission) becomes lánchead (full permission).
réamh-   pre-, preliminary
Example: feiceáil (seeing) becomes reamhfheiceáil (foresight).
mion-   small, micro-
Example: insint (telling) becomes mioninsint (detailed report).
sár-   exceeding, ultra-
Example: riail (') becomes sár-riail (golden rule).
ró-   over-
Example: minic (often) becomes rómhinic (too often).
so-   easy
Example: briste (broken) becomes sobhriste (fragile, easily broken).