Question: “Hardly”, “hardly ever”, and “hardly even” seem to mean different things and I can hardly distinguish between them.

There's [this page](http://www.learnersdictionary.com/search/hardly), listing 2 very similar meanings for *hardly*, and which seems to indicate [here](http://www.learnersdictionary.com/search/ever) that it composes “normally” with *ever* (i.e. *hardly* + *ever* = *almost* + *n+ever*), but doesn't mention *even*.

Also, I can't help but believe there should be a way to understand it as *in a hard way* (*hard-ly*), but I can't find it.

What's a clear way to understand all this?

Answer: 
The meaning of *hardly* has evolved over the centuries. So has the meaning of the adjective from which it is derived, *hard*. But where the adjective has **accumulated** meanings, so most of its meanings are still alive in one context or another, *hardly* has drifted from meaning to meaning.

I won't trouble you with the entire history (which you may find in the [Oxford English Dictionary](http://archive.org/stream/newenglishdicpt105murruoft#page/84/mode/2up)—look at *Hard*, both adjective and adverb, and *Hardly*); but by about 1600 *hard* had the senses of *difficult* and *close, narrow*, and both of these may be detected behind the modern sense of *hardly*. 

When a historian writes that “The King **hardly** escaped, by charging with his own troop of horse solely, through the body of the enemy” he implies both that Charles escaped only *with difficulty* and that he escaped only *narrowly*” — *by the skin of my teeth*, we also say. 

When Captain Corcoran boasts that he “never” curses, and then admits that it’s actually “**hardly ever**”, he’s claiming that it’s so *close* to “never” that it’s not worth dwelling on. In fact, it’s **hardly even** worth mentioning—very *close* to being not even worth mentioning at all.

In today’s use the *difficulty* sense has declined, but it’s kept alive by uses like the old song “Johnny I **Hardly** Knew Ye” in which a woman meets her old love who has been almost unrecognizably disfigured in war.
The way to understand it it's almost synonymous with "barely" except it's not satisfactory.

"The food storage barely suffices for the winter" means with rationing meals people will pass the winter without starving but never full. It's not optimal, but it's acceptable.

"The food storage hardly suffices for the winter" means it will suffice to survive the winter but people will be starving. They won't die, but they will definitely feel strong hunger and lose weight. It's not something you should accept unless you have no other options.

Another example:

"I barely passed the exam" - I needed score 40/100 and got 40 points. I can go have a drink and relax. It's not a stellar score but the job is done.

"I hardly passed the exam" - I needed score 40/100 and got 42 points. Technically, I passed. But the score counts towards global score which is required to advance to next year. Currently, with this exam I have 598/600 required and it means despite passing this exam I won't advance to the next year. I must approach this exam again and finish it with at least 44 points, then I will have barely passed into next year.

"Hardly" is sometimes an euphemism for "no". "That's hardly enough" usually means "do more, it's still not enough".