Former president familiarly ignoring bill for sailing ship (4)
I believe the answer is:
bark
'sailing ship' is the definition.
(bark is a kind of sailing ship)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for bark that I've seen before include "Tree's outer layer" , "Dogs might react to this part of a tree" , "Hardly a sound from Tom" , "Tree-skin or dog noise" , "Section of tree" .)