Peruse most properly means to read something carefully and thoroughly, as a lawyer might peruse a contract line by line, though in everyday use people also say peruse to mean a casual look, which can cause confusion. Skim, by contrast, always means reading quickly and picking up only the main points, the way you'd skim a report before a meeting instead of reading every word.
The core difference
Peruse traditionally means to read closely, while skim always means to read quickly and superficially.
- peruse — to read carefully and thoroughly (though also used loosely for a casual look): The lawyer perused the contract line by line before signing.
- skim — to read quickly, picking up only the main points: I skimmed the report before the meeting instead of reading it word for word.
How to tell them apart
Peruse is one of those words with two accepted but opposite-feeling meanings: its careful, close-reading sense is the traditional one, but it's now also used casually to mean flicking through something, the way you might peruse a magazine while waiting for coffee. If you want to be understood clearly, it helps to know your audience — in formal writing, peruse usually signals careful attention.
Skim doesn't have that ambiguity. It always implies speed and a light touch, whether you're skimming a document for the gist or skimming a stone across water. When precision matters, skim is the safer word if quick and shallow is what you mean.
