Irksome is an adjective that means annoying.

To irk someone is to annoy or irritate them. When we combine this word of Middle English origin with the suffix S-O-M-E, which means ‘tending to cause,’ we get a word for a person or thing that tends to annoy or irritate.

Don’t get me wrong, Craig is a great co-worker to have. But his habit of singing in his cubicle non-stop can get a bit irksome after several hours.