To hit something or someone with a glancing blow on the side; or to criticize someone indirectly or incidentally.
From 'side' + 'swipe' (to strike). The compound became common in early 20th century as automobiles became prevalent, describing how cars would hit each other at an angle.
The figurative meaning—indirect criticism—is interesting because it mirrors the physical meaning: you hit someone but not directly, from the side. It's become common in social media culture for indirect callouts.
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