Superlative form of 'dry'; having the least moisture of all; also means most boring.
From Old English 'dryge,' possibly from Proto-Germanic 'drugiz' meaning 'firm, solid.' The extended meaning of 'boring' comes from 'dry wit' (emotionless humor).
The 'driest wit' is actually hardest to pull off—it requires a completely straight delivery and often goes over people's heads, which is why characters with dry humor (like deadpan comedians) require an intelligent audience to land their jokes.
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