dope — any thick liquid or pasty preparation, as a lubricant, used in preparing a surface.
dork — Slang. a silly, out-of-touch person who tends to look odd or behave ridiculously around others; a social misfit: If you make me wear that, I’ll look like a total dork! Synonyms: jerk, schmo; nerd, geek.
dumbbell — a gymnastic apparatus consisting of two wooden or metal balls connected by a short bar serving as a handle, used as a weight for exercising.
dummy — a representation or copy of something, as for displaying to indicate appearance: a display of lipstick dummies made of colored plastic.
dunce — a dull-witted, stupid, or ignorant person; dolt.
fool — to trick, deceive, or impose on: They tried to fool him.