Tedious is applied to something which tires us out by the length of time occupied in its performance; as, a tedious speech. Pity only on fresh objects stays, But with the tedious sight of woes decays.

Webster's Revised Unabridged Dictionary (1913)

Example sentences

boring The show was so boring that Ann and I fell asleep.
tiresome I never, ever want to do that tiresome work again.
irksome Being treated as a minor is irksome.
wearisome The work required to investigate that is boring and wearisome.
prolix Many readers will get lost if your writing is too prolix.

Popularity over time

Word	1850 → 2019	Trend
tedious		steady
boring		rising
tiresome		steady
irksome		steady
wearisome		steady

Use in printed books, per decade from 1850 to 2019.

By length

4 letters: slow¹, dull¹
5 letters: heavy², windy², banal², wordy², vapid²
6 letters: boring², mortal², tiring², dreary², prolix
7 letters: lengthy², mundane², prosaic³, humdrum², verbose, irksome²
8 letters: sluggish², tiresome³
9 letters: laborious⁴, fatiguing³, soporific, wearisome³
10 letters: monotonous⁴
11 letters: repetitious⁴
13 letters: uninteresting⁴

The small number after each word is its number of syllables (heavy² = 2 syllables).

In other languages

Français: fastidieux
Italiano: noioso
Español: tedioso