Insinuating means hinting at something unpleasant without ever saying it. The suggestion is there and nothing can be pinned on it.
It describes tone, questions and smiles, and an insinuating manner is one that makes everybody uncomfortable without giving them anything to object to. That deniability is the whole technique. The verb insinuate is used constantly in the challenge what exactly are you insinuating. There is a second and physical sense, since insinuating yourself into a group means working your way in gradually and unnoticed.
1adjectiveinsinuatingHinting at something unpleasant without stating it.
“He asked the question in a horribly insinuating tone.”
Latin
īnsinuātus
English
insinuate
English, today
insinuating
Built from
insinuate 1529; Latin īnsinuātus, perfect passive participle of īnsinuō (“to push in, creep in, steal in”) (see -ate and -ate), from in- (“in”) + sinus (“a winding, bend, bay, fold, bosom”) -ō. Regular participial usage of the adjective up until Early Modern English.
Etymology from Wiktionary, CC BY-SA