This word orignated from Birmingham, England and is the word "rees" backwards (see "rees" in the urban dictionary for definition). It has the same meaning as the word rees but is a different and possibly more extreme was of calling somebody a "rees" or "resol".
"HAHA look at Brendon Hanrahan's hair!"
"HAHAHAHA what a seer!"
short for "serious", common lingo between douche bags and fags. Other common words are used such as "yon" and "non"
mike: Lets go skate
billy: are you seer?
mike: you are a douche, i dont want to go anymore