A fork of Rural Dictionary
Foul mood can best be described as a mood in which one no longer feels happy or content. Foul moodedness can be associated with being grumpy, being an asshole, or just flat out being a cunt to others. One who is in a foul mood will not want to deal with stupid people, talk to anyone, or may feel the need to curse anyone or anything out.
I was working and having such a great day today. Then a customer told me I was stupid and ruined it. I'm in such a foul mood right now.