General terms:
* Subtext: This is a common term for the unspoken meaning or implication in a text, conversation, or piece of art.
* Implication: This word suggests a hidden meaning that is not explicitly stated but can be deduced from what is said.
* Innuendo: This is a more suggestive term, implying a hidden meaning that is often sexually suggestive or insulting.
* Undercurrent: This emphasizes a subtle, underlying feeling or theme that runs through a conversation or situation.
More specific terms:
* Connotation: This refers to the associated meanings and emotions attached to a word or phrase beyond its literal definition.
* Double entendre: This is a phrase or statement that has two meanings, one of which is often suggestive or humorous.
* Allusion: This is a reference to something else, often a literary work, historical event, or person, which can imply a hidden meaning.
The best word to use will depend on the specific context and the type of underlying meaning you want to emphasize.