Nerve injuries are graded by Seddon into three types of increasing severity. The question asks for the meaning of the first and mildest type, $neurapraxia$.
In neurapraxia the insult is essentially a focal $demyelination$ of a nerve segment, most often from compression or stretch (e.g., "Saturday night palsy"). The crucial point is that the underlying $axon$ stays anatomically continuous and all connective-tissue layers are undamaged. What is lost is the ability to conduct an impulse across that segment - hence a purely $physiological$ block.
Two consequences follow. First, since the axon is not severed, $Wallerian$ degeneration does not take place distally. Second, recovery is the rule and is rapid, occurring over days to a few weeks as the segment remyelinates; nerve conduction studies show conduction block but preserved distal responses.
Contrast this with the distractors: cutting the axon while sparing the endoneurial tube is $axonotmesis$, and division of the axon together with its sheaths is $neurotmesis$. Both of these provoke Wallerian degeneration, unlike neurapraxia.
\[\boxed{\text{Neurapraxia} = \text{physiological conduction block, axon intact}}\]