The definition of the words below have been taken from the book From Red to Black.
networth: value of assets less debt.
investment debt: debt against investments that will increase in value and increase your networth.
killer debt: debt is used to buy things that go down in value, or things that have no value at all (like holidays).
solvent: having more assets than debt; it means being able to pay one’s debts and bills in full.
solvency: the ability to pay one’s debts and bills in full.
viability: income is greater than or equal to your living expenses.