almost not
"he hardly ever goes fishing"
"he was scarce sixteen years old"
"they scarcely ever used the emergency generator"
"I can hardly hear what she is saying"
"she barely seemed to notice him"
"we were so far back in the theater, we could barely read the subtitles"
Firmly, vigorously, with strength or exertion.
"He hardly struck the ball, sending it flying across the field with tremendous force."
In plain English: Hardly means almost not at all, so it is used to show that something happens very rarely or just barely enough.
"I can hardly believe how fast time flies when we are having fun with friends."
Usage: Hardly means barely or almost never and should not be used to mean firmly or vigorously as that is the definition of hard. Use hardly only when you want to indicate a very small amount or low frequency of an action.
Not really.
"The project was hardly finished when the power went out."
From Middle English hardely, hardliche, from Old English heardlīċe ("boldly; hardily; without ease; in a way that causes pain; not easily; only by degrees"), equivalent to hard + -ly. Compare Dutch hardelijk, German härtlich.