A high-ranking military official, marshal, or scribe-commander. Borrowed from Akkadian, this word appears in descriptions of Babylonian military hierarchy. These were the officials who administered conquered territories and managed the machinery of empire.
The tiphsar represents human imperial power in its organized, bureaucratic form — the very system God repeatedly humbles. Jeremiah invokes these officials as part of the Babylonian army that God uses as His instrument of judgment, then later judges in turn. It reminds believers that empires have structure and strength, but they serve a purpose only as long as God permits.