Sticking the neck out

Neck is കഴുത്തു്. Its root, കഴു.

Let us look at some other words that start with കഴു:

• കഴുമരം - gallows (കഴു + മരം )
  
• കഴുവേറി (offensive, use carefully) - thief (കഴു + ഏറി)
  

All linked to the meaning of neck. But how about:

• കഴു - to wash (കഴുകുക)
• കഴുത - donkey!
• കഴുകന്‍ - vulture

Not sure how these are linked to neck. One might argue that the load is put on a donkey's back or around its neck. Also, the vulture has an especially curved neck.

But how about the meaning of "to wash"?