IPA: /ˈtaɪərsəm/
KK: /ˈtaɪərsəm/
Causing tiredness or boredom; something that is dull and uninteresting.
The lecture was so tiresome that many students fell asleep.
Comparative: more tiresome
Superlative: most tiresome
Tiresome → It is formed from "tire" (from Old French *tirer*, meaning to pull or draw) and "-some" (meaning characterized by or causing). The word "tiresome" means characterized by causing fatigue or weariness.
Think of something that 'pulls' or 'draws' energy from you ('tire') and remember that 'tiresome' describes something that makes you feel weary.