What kind of wordplay is this?

In his book Humorous English, Evan Esar gives example uses of devices he broadly labels synonymics. He writes of synonymic puns:

• Many a wife sends her husband to an early grave with a series of little digs.
• They are made for each other. He owns oil wells, and she's always gushing.

The cleverness of these jokes consists in their use of commonly associated words—grave and digs in the first, oil wells and gushing in the second.

And of synonym grouping:

• Our florist has two children—a girl who's a budding genius and a boy who's a blooming idiot.
• I went to see a spiritualist. She wasn't good, just medium.

Similarly, these jokes rely on the use of closely related words—florist, budding, and blooming; and spiritualist and medium (intended both as the noun meaning spiritualist and as the comparative between good and bad).

Throughout the book, which is a catalogue of comedic techniques, Esar coins original terms for the phenomena he describes, and so they aren't to be found elsewhere. The use of synonym to describe these devices seems a bit misleading, because they don't use synonyms. They do, however, use words that are quite closely related (but aren’t synonymous). Does anyone know of a technical term for this kind of wordplay? And does anyone know of any examples of its use anywhere else?

These are examples of a witticism known as Puns.

noun

1. the humorous use of a word or phrase so as to emphasize or suggest its different meanings or applications, or the use of words that are alike or nearly alike in sound but different in meaning; a play on words.