Yep, for real. It’s military speak and according to OED it has a few decades under its belt.
Etymology: Back-formation < exfiltration n.
Mil. (orig. U.S.).
trans. and intr. To withdraw (troops, spies, etc.) from a dangerous position, usu. surreptitiously. Opp. infiltrate v. 4.
1980 Christian Sci. Monitor 1 May 4/4 US special forces agents who infiltrated Iran to prepare and assist in the later phases of the actual rescue in Tehran reportedly have all been ‘exfiltrated’ safely from Iran.
The older scientific term exfiltration:
Etymology: n. of action < ex- prefix1 + -filt- + -r- (in filter n.): see -ation suffix.
The action or process of filtering out.
1878 P. H. Lawrence tr. B. von Cotta Rocks Classified 25 Zeolites ‘are products of exfiltration or of the internal decomposition and transmutation of the mother rock.’
Pipped by lh!