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Webster 1828 Edition

adv.

Peevishly; angrily; tartly.

snappishly ‎(comparative more snappishly, superlative most snappishly)

In a snappish manner.
- 1950, C. S. Lewis, The Lion, the Witch and the Wardrobe, Collins, 1998, Chapter 4,
  Lucy […] was too happy and excited to notice how snappishly Edmund spoke or how flushed and strange his face was.