the.com/ailment

means A sickness or physical complaint, usually minor, that's bothering you.

from From the verb 'ail,' meaning to trouble or afflict, which traces back to Old English 'eglan.' The '-ment' was bolted on in the 18th century to turn the verb into a noun — so an ailment is, quite literally, just 'the thing that ails you,' freshly packaged as a word of its own.