Negligible comes from the same Latin verb as neglect, so something negligible is literally "neglectable".

What is the correct meaning of the world negligible?

adjective. so small, trifling, or unimportant that it may safely be neglected or disregarded: The extra expenses were negligible.

What is the meaning of negligible cost?

Ineligible Costs means those Project Costs incurred by the Recipient and which are not Eligible Costs as set out in Annex 1 – Statement of Work.