A deductible is the insured's share of each loss. With a $5,000 deductible, the sub pays the first $5,000 of a covered claim and the insurer pays the rest up to the limit. Higher deductibles usually mean lower premiums.
For GCs, an unusually high deductible can be a yellow flag: if a sub cannot fund their deductible, a claim may stall. It is one of several policy details worth noting during review.