Undermine

Practical Literary politics work psychology

Etymology

A plain compound of “under” and “mine,” in the old military sense of mining: digging tunnels beneath a fortress wall so it would collapse under its own weight. The figurative meaning preserves the tactic exactly — attack the support, not the surface.

verb · /UHN-der-myne/
To weaken something gradually and often secretly, from a position beneath or behind it.
What it names
Sabotage-by-erosion — the slow hollowing-out that makes a thing collapse without a visible blow.
Example
Every time he corrected her in front of clients, he undermined the authority she needed to do the job.
Related idea
To undermine is to weaken something sound from below; to bolster is to prop it up. The word’s power is in its stealth — you rarely see the tunnel until the wall falls.
verb · /UHN-der-myne/
To dig or wear away the base of something, so that it collapses or is left unsupported.
What it names
literal erosion or excavation beneath a structure
Example
The river had undermined the bank until the fence toppled into the water.
Related idea
The figurative sense is a straight metaphor from siege warfare and erosion — attack the foundation, not the visible top. Compare insidious.