"peskiest" in the adjective sense
1. annoying, bothersome, galling, irritating, nettlesome, pesky, pestering, pestiferous, plaguy, plaguey, teasing, vexatious, vexing
causing irritation or annoyance
"tapping an annoying rhythm on his glass with his fork"
"aircraft noise is particularly bothersome near the airport"
"found it galling to have to ask permission"
"an irritating delay"
"nettlesome paperwork"
"a pesky mosquito"
"swarms of pestering gnats"
"a plaguey newfangled safety catch"
"a teasing and persistent thought annoyed him"
"a vexatious child"
"it is vexing to have to admit you are wrong"
Source: WordNet® (An amazing lexical database of English)
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