An innuendo is an insinuation or intimation about a person or thing, especially of a disparaging or a derogatory nature. It can also be a remark or question, typically disparaging (also called insinuation), that works obliquely by allusion. In the latter sense the intention is often to insult or accuse someone in such a way that one's words, taken literally, are innocent.
According to the Advanced Oxford Learner's Dictionary, an innuendo is "an indirect remark about somebody or something, usually suggesting something bad, mean or rude", such as: "innuendos about her private life" or "The song is full of sexual innuendo". 
The term sexual innuendo has acquired a specific meaning, namely that of a "risqué" double entendre by playing on a possibly sexual interpretation of an otherwise innocent uttering. For example: "We need to go deeper" can be seen as either a request for further inquiry, or a request to go deeper into an intimate part.
In the context of defamation law, an innuendo meaning is one which is not directly contained in the words complained of, but which would be understood by those reading it based on special knowledge.
Television and other media
The figure on the right shows a male cat paying a "call" on a female cat, who then serves up kittens, insinuating that the "result" of children is predicated on a male "call".
Many television shows aimed at a younger audience frequently use innuendos as a way of attracting older viewers without offending their network's censorship.
Many American primetime shows use an extensive amount of innuendo to the point that it is rated TV-PG/14 D for dialogue. Shows such as American Dad!, Tosh.0, and especially Family Guy and South Park have done this. Also, many radio shows, including the Bobby Bones Show, the Rick and Bubba Show, The Gallo Radio Show, and most of the songs played on Southern Crossroads are notable for this.
On The Scott Mills Show on BBC Radio 1, listeners are asked to send in clips from radio and TV with innuendos in a humorous context, a feature known as "Innuendo Bingo". Presenters and special guests fill their mouths with water and listen to the clips, and the last person to spit the water out with laughter wins the game.
- Oxford Advanced Learner’s Dictionary (7th Edition; electronic version)
"Going down: 'Grace Bros' store closes". BBC News. February 1, 1999.
The innuendo was loud and clear
Dominic Cavendish (31 Oct 2003). "A return to unalloyed joy". The Telegraph.
...a censor-baiting mixture of absurd spoofs, yarns, links and character-turns, laced with end-of-the-pier innuendo and erudite-infantile wordplay.
"Only The Brits: Not Christmas Without Pantomime". NPR. December 25, 2011.
No panto is complete without a dose of smutty innuendo for the adults and some contemporary political jokes.
- "Innuendo Bingo". Retrieved 15 October 2012.