Tiresome means boring, annoying, or exhausting in a way that drains your patience or energy. When something is tiresome, it makes you feel weary, not necessarily from physical effort but from repetition, dullness, or irritation.

A tiresome task might be copying the same math problem fifty times: it's not hard, just tedious and draining. A tiresome person talks endlessly about themselves without noticing that others have stopped listening. Long car trips can become tiresome when you're stuck in the backseat with nothing to do. Even fun activities can grow tiresome if repeated too often without variety.

The word suggests something that wears you down gradually. One reminder to clean your room isn't tiresome, but being nagged about it every ten minutes becomes tiresome quickly. One question isn't tiresome, but answering the same question over and over definitely is.

Notice how tiresome differs from merely tiring: climbing a mountain is tiring (physically exhausting) but might be thrilling. Listening to someone complain about the same problem for the hundredth time without doing anything about it is tiresome (mentally draining and frustrating). When something is tiresome, you find yourself thinking, “Not this again.”