adj. 25B6; adjective STEALTHY, subtle, surreptitious, cunning, crafty, artful, sly, wily, underhand, backhanded, indirect; informal sneaky.
INSIDIOUS
Meaning of INSIDIOUS in English
Concise Oxford thesaurus English vocabulary. Краткий оксфордский словарь английского языка тезаурус. 2012