The word of "Doh", or more importantly sound of "Doh", is used in (but is not limited to) two meanings:
1. In substitution for a phrase implying
something along the lines of: "He/She/They would...'''
2. A response to a thing, or situation, that is extremely lacking in
intelligence.
(See Examples For Further Details)
*Contrary to popular belief, the pronunciation of "Doh" is actually more along the lines of "Cho" and most commonly assisted by a
dip of the chin/drop of the shoulders.*
Ex 1:
Guy 1: "Dude, Terry just tried to tell me that, because of a
chip he bought online, his stock Dodge Neon, now has 500 horsepower and is faster than/equivalent to the speed of
light."
Guy 2: "Doh..."
Ex 2:
Guy 1: "I strongly believe that if I worked out for a good... 30 days non-
stop, I could lift more than Ronnie Coleman in his prime."
Guy 2: "Doh..."