Derogatory term for a farmer or peasant, often implying rustic ignorance or low social status. The prefix ど adds contempt. Compare with 百姓 (ひゃくしょう), which can be neutral or mildly derogatory depending on context.
農民 is a neutral, standard term for farmer or peasant, without derogatory connotations.
Etymology
The prefix ど is a derogatory intensifier, possibly related to the prefix ど- in words like ど真ん中 (dead center) or どぎつい (harsh). The exact origin is uncertain. 百姓 originally meant 'common people' or 'farmers'.