ichidan verb
strip the head of a screw; wear out threads
Rare term used for damaging a screw, bolt, or similar fastener so that the head or threads become rounded and the tool can no longer grip. Often used in DIY or mechanical contexts.
ネジをなめかけてしまって、もう回せない。
I stripped the screw and now I can't turn it.
なめる means 'to lick' or 'to taste', while なめかける is a compound verb specifically meaning 'to strip a screw head'.
A more common and explicit phrase for stripping screw threads. なめかける is rarer and more colloquial.
Compound of なめ (from 嘗める, 'to lick', here metaphorically 'to wear smooth') + かける (掛ける, 'to start' or 'to be in the process of'). The exact derivation is uncertain, but the image is of a screw head becoming smooth like a licked surface.