Synonyms for boring

These adjectives refer to what is so uninteresting as to cause mental weariness. Boring implies feelings of listlessness and discontent: I had never read such a boring book.
What is monotonous bores because of lack of variety: “There is nothing so desperately monotonous as the sea” (James Russell Lowell).
Tedious suggests dull slowness or long-windedness: Traveling by plane avoids spending tedious days on the train.
Irksome describes what is demanding of time and effort and yet is dull and often unrewarding: “I know and feel what an irksome task the writing of long letters is” (Edmund Burke).
Something tiresome fatigues because it seems to be interminable or to be marked by unremitting sameness: “What a tiresome being is a man who is fond of talking” (Benjamin Jowett).
Humdrum refers to what is commonplace, trivial, or unexcitingly routine: My quiet cousin led a humdrum existence.