English
gnatproof
From gnat + -proof.
Formed from gnat + -proof
Proto-Indo-European *gʰen- ‘to gnaw’
…
Proto-Germanic *gnattaz ‘a biting insect’
Proto-West Germanic *gnatt ‘gnat, mosquito’
Old English gnætt
Middle English gnat ‘a gnat or similar insect’
English gnat
Today it means
adj Resistant to gnats.
Language periods are conventional ranges, not dates for this word.
Etymograph / gnatproof