[ dee-purm ]
/ diˈpɜrm /

verb (used with object) Nautical.

to reduce the permanent magnetism of (a vessel) by wrapping an electric cable around it vertically athwartships and energizing the cable.
Compare degauss.

Origin of deperm

First recorded in 1945–50; de- + perm(anent) Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019