【Insinuation】 , 【innuendo】 mean covert suggestion or a covert allusion to something.
【Insinuation】 applies chiefly to a remark, comment, or question which conveys or seems to convey a hint or implication, often one that is discreditable to the person at whom it is aimed.
【Innuendo】 more often applies to the method of covert suggestion than does 【insinuation】 , and when it applies to a definite instance, it is referable to meaningful smiles, glances, inflections, as well as to remarks; in both cases the term definitely implies a suggestion of something that is injurious to the reputation of the person concerned.