In military brevity terms, what does the code "VANISHED" indicate?

The code "VANISHED" is utilized in military brevity communication to indicate that contact has been lost with a target or unit. This term is crucial for maintaining situational awareness in the fast-paced environment of military operations, as it alerts all parties involved that there is no longer a visual or electronic track on the subject in question. Such communication helps in assessing battlefield status and reinforces the need for further actions to re-establish contact or adjust tactics accordingly.

In assessing the context of the other options, while engagement success or completion of a mission might imply a decisive outcome, those scenarios do not necessarily reflect a loss of contact, which is the specific implication of "VANISHED." Similarly, declaring the enemy status as "unknown" would not accurately capture the precise situation indicated by the term, which focuses explicitly on the loss of engagement rather than ambiguous status.