Allowable :: Allowable (a.) Proper to be, or capable of being, allowed; permissible; admissible; not forbidden; not unlawful or improper; as, a certain degree of freedom is allowable among friends..
Allowableness :: Allowableness (n.) The quality of being allowable; permissibleness; lawfulness; exemption from prohibition or impropriety.
Allowably :: Allowably (adv.) In an allowable manner.
Disallowable :: Disallowable (a.) Not allowable; not to be suffered.