Select the wrongly spelt word.

English does not simply glue a suffix onto a verb: forming a noun often reshapes the stem, so a noun cannot be spelt by copying the verb it came from. Two habits of the language decide a word like this. A verb ending in -tain keeps its spelling before the plain suffix -ment, as in attain and attainment, but loses the -ai- when the noun is built on a Latinate ending such as -ance, -ence or -tion. Separately, a small family of verbs led by argue drops the silent -e before -ment, even though most verbs, such as move in movement, keep it. A spelling item is therefore settled by checking each printed form against the standard dictionary form, not against the verb behind it.

Applying this to the four printed words:

1. Argument comes from argue, one of the few verbs that drop the silent -e before -ment, unlike move in movement or state in statement, so the standard form carries no e after argu-, and the printed form agrees with it.

2. Calendar, the chart of dates, descends from Latin kalendarium and ends in -ar, and the printed form agrees with it; the -er spelling calender is a separate word naming a machine that presses cloth.

3. Surprise is sur- plus prise from Old French surprendre and keeps both r letters, and the printed form agrees with it.

4. Maintenance is the noun of maintain built on the Latinate ending -ance, so the -ai- of the verb is lost and the standard form is main-ten-ance. The printed form Maintainance carries -tain- straight over from the verb and therefore departs from the standard spelling.

Cross-check the same loss of -ai- wherever a -tain verb takes a Latinate ending:

• sustain gives sustenance, never sustainance.

• abstain gives abstinence, never abstainance.

• detain gives detention and retain gives retention, while the plain -ment nouns attainment and containment keep the -ai- untouched.

The wrongly spelt word is therefore Maintainance, whose standard spelling is Maintenance.