The present paper discusses the Russian lexemes горлопан ‘shouter, bawler’ and крыса ‘rat’, which are problematic from the point of view of etymology. The word горлопан can be explained as a compound, connected by grade haplology to Russian dialectal лопать ‘to shout’ and горло ‘throat’: горлопан = горло-лоп-ан > горлопан (because of expressivity). The Russian word крыса is seen as an expressive doublet to Slavic gryz-. The paper is based on historical and lexicological material, and uses dialectal examples that ensure the reliability of conclusions. The author pays particular attention to the semantic, phonetic, and derivational aspects of the etymology of the word.