In this MSO question, the author refers to himself as sounding like a "tool". What does this mean? Specifically, the way it is used in the linked question implies that being a tool means being pompous or infatuated with oneself, whereas the urban dictionary and wiktionary write that it means one is being used without knowing it. Is the way it is used in that question an acceptable variant or did the OP make a mistake in usage confusing a popular word for a different concept?
Learn English – What does “tool” really mean
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Best Answer
According to Green's Dictionary of Slang, tool has several meanings. In the current context it would probably mean "a stupid, useless or socially inept person". The first citation for this dates from 1656.
I suspect that this meaning is derived from the first meaning under the headword "tool", "the penis", as a literal or figurative bodily organ (first citation 1553), as names for the reproductive organs are frequently employed as terms of abuse (can't think why).
The meaning of "unskilful workman" appears a little later, at 1698.