A person who is deficient.
Insufficient or inadequate in amount.
Lacking something essential; often construed with in.
Of a number n, Having the sum of divisors σ(n)<2n, or, equivalently, the sum of proper divisors (or aliquot sum) s(n).
A dirty, grimy, sleazy, or disreputable person.
A poor climber, alpinist, skier or other outdoorsman who lives cheaply, without normal employment, and with few amenities in order to spend as much time on their sport as possible. Used praisingly.