A word that was come up with to express: annoyance, irritation, anger, unamusment, unimpressed, ticked, pissed off.
It is a colloquial term, often just randomly thrown into the midst of a conversation simply either because no other word would suffice, or because all of the above are being expressed at the same time.
The word was originally used in the Stargate SG1 episode 'Fragile Balance' to express O'Neill's annoyance for the sudden crashing of events upon him.
"I just woke up, haven't had coffee, let alone a PEE 7 days, I should currently be 'irked', Carter, should I not?"~ ep. Fragile Balance, Stargate SG1
"I thought you might still be irked at me from the other night."