隙 - crevice, fissure, discord

gap; opening; room; space

gap; opening; aperture; crevice; crack; chink; space

before one could; in no time at all; without a gap

time flies; like watching a white horse run by through a gap in the wall (Zhuangzi)

spare moment; free time; interval; break

porosity

God of the gaps

potential space

closely; compactly; leaving no space

crack; slit; crevice; crevasse

without any weak spot; watertight (e.g. reasoning); impeccable

to watch for an unguarded moment