diff --git a/man2/umount.2 b/man2/umount.2
index 5ff88152c..aea39d830 100644
--- a/man2/umount.2
+++ b/man2/umount.2
@@ -66,9 +66,10 @@ This can cause data loss.
 (Only for NFS mounts.)
 .TP
 .BR MNT_DETACH " (since Linux 2.4.11)"
-Perform a lazy unmount: make the mount point unavailable for
-new accesses, and actually perform the unmount when the mount point
-ceases to be busy.
+Perform a lazy unmount: make the mount point unavailable for new
+accesses, immediately disconnect the filesystem and all filesystems
+mounted below it from each other and from the mount table, and
+actually perform the unmount when the mount point ceases to be busy.
 .TP
 .BR MNT_EXPIRE " (since Linux 2.6.8)"
 Mark the mount point as expired.