neprātis

From neprāts (“irrationality”) (itself from ne- +‎ prāts (“reason, understanding, mind”)), made into a 2nd-declension masculine noun.

neprātis m (2nd declension, feminine form: neprāte)

1. (male) fool (man who behaves or acts without thinking, against common sense)

   novakarē šad un tad satika pa automobilim; pieradušie zirgi baidījās tikai tad, kad kāds neprātis visā sparā drāzās garām ― in the evening now and then a car appeared; the horses, already accustomed, were afraid only when some fool rushed by at full speed

2. (male) madman (man with serious mental problems)

   viņš pēkšņi sāka jaukt dejas soļus, kā pēdējais neprātis ― he suddenly started making dance steps, like the worst (lit. last) madman

3. foolhardy, reckless man

   noskaidrojās, ka kņadā iejaucies Kaugurmuižas stārasts un tad daži neprāši gribējuši arī viņu pārmācīt ― it turned out that the headman of Kaugurmuiža and then a few fools who wanted to teach him a lesson got involved in the mess (= fight)

• (of "fool"): duraks, idiots, muļķis, muļķadesa, nejēga, stulbenis
• (of "madman"): ārprātīgais

• neprātība
• neprātīgs, neprātīgums