From chathar; a burglary; figuratively, unexpected examination -- breaking up, secret search.
see HEBREW chathar
H4290. machtereth
מַחְתֶּ֫רֶת noun masculine breaking in, burglary — ׳אִםבַּֿמּ הַגַּנָּב יִמָּצֵא Exodus 22:1 i.e. caught in the act (JE); so בַּמּ ׳לֹא מְצָאתִים Jeremiah 2:34, not in the act of breaking in didst thou find them (2 feminine singular suffix Ges§ 44, 2, R 4), i.e. those whom thou hast slain were not detected in crime.