What does “comb-over” mean in the line, “Overused / abused words, e.g.’twerking’ and ‘stay classy’ are the aural equivalent of a comb-over”?

The New York Times (December 28) article, Words for the Dumpster begins with the following sentence:

With the last tick of 2013, let’s throw out the most annoying, overused and abused words of the year. A few of these terms, “twerking” or “stay classy,” die a natural death when someone like John McCain starts using them — the aural equivalent of a comb-over. Others need a push.

Merriam-Webster Dictionary defines “comb-over” as:

an arrangement of hair on a balding man in which hair from the side of the head is combed over the bald spot.

I understand “comb-over” also means to investigate / search for thoroughly. But neither seems to be relevant to the usage of “comb-over” in the above quote.

What does the author means by saying “A few of overused and abused words of the year die a natural death when someone like John McCain starts using them — the aural equivalent of a comb-over.”?

A comb-over is an attempt by an elderly or prematurely balding man to disguise his baldness and appear more youthful and attractive by growing his top hair very long and combing it over the bald spot. It is rarely effective and usually risible.

The expressions cited by your author in this sentence are youthful slang—language whose primary purpose is to mark membership in a fashionable speech community. He is pointing out that once these expressions become so widely known that even an ancient and conservative politician like John McCain employs them in the vain attempt to appear younger and more "with-it"^† than he is, they cease to be of value to those who coined them.

^†coined ca. 1961; †1975

To comb something means to look it over carefully; to search everywhere in: He combed the files for the missing letter. One can also comb through.

The hyphenated word comb-over is, indeed, an arrangement of hair on a balding man in which hair from the side of the head is combed over the bald spot. It is sometimes left unhyphenated.

The NYT author is saying that when elderly statesmen like John McCain starts using a trendy word, the word will be looked upon as a bad thing, no longer trendy and youthful, but distasteful, a bad fate for a word — the aural equivalent of a comb-over.

Good: a full head of hair, or a bald head.

Bad: A bald spot with a bad comb-over.