The English word for vivac is

The English word for "vivac" is "bivouac." Bivouac refers to a temporary encampment, typically without tents or cover, used by soldiers or mountaineers. It can also be used as a verb to mean to set up such an encampment. For example, if a group of hikers decides to set up a temporary camp in the mountains without tents or cover, they could say that they are bivouacking. Therefore, "fast and lively," "slow," and "sustained" are not related to the meaning of vivac or bivouac, so they are not the correct answer. "Slow and steady" could describe the pace at which someone sets up a bivouac, but it is not the actual word for vivac.