Other forms: pinpointed, pinpointing, pinpoints
To pinpoint is to locate or identify something exactly. Pinpoint the fault, pinpoint accuracy, hard to pinpoint.
It means exactly rather than roughly, which is why pinpoint accuracy is a fixed phrase. The image is a point small enough to be marked with a pin. Hard to pinpoint is a useful admission that you know something is wrong but not what.
1verbpinpointTo locate or identify something exactly.
“Engineers are still trying to pinpoint the cause of the power cut.”
pinpoint is a locating.
Pin plus point, first the tiny point itself, then the verb, from the twentieth century.
From pin + point.
Etymology from Wiktionary, CC BY-SA