AIR - The atmospheric substance above the surface of the earth which animals breathe, formerly considered to be a single substance, one of the four basic elements of ancient philosophy and one of the five basic elements of Eastern traditions.
ILL - Extremely bad (bad enough to make one ill). Generally used indirectly with to be.
LAP - The loose part of a coat; the lower part of a garment that plays loosely; a skirt; an apron.
LIP - Either of the two fleshy protrusions around the opening of the mouth.
PAL - A friend, buddy, mate, cobber, someone to hang around with.
PAR - By; with.
RAP - A sharp blow with something hard.
RIP - A tear (in paper, etc.).
AIL - Painful; troublesome.
LIAR - One who tells lies.
PAIR - Two similar or identical things taken together; often followed by of.
PILL - A small, usually cylindrical object designed for easy swallowing, usually containing some sort of medication.
RAIL - A horizontal bar extending between supports and used for support or as a barrier; a railing.
LAIR - A place inhabited by a wild animal, often a cave or a hole in the ground.
PAIL - A vessel of wood, tin, plastic, etc., usually cylindrical and having a handle -- used especially for carrying liquids, for example water or milk; a bucket (sometimes with a cover).
PALL - Fine cloth, especially purple cloth used for robes.
PILLAR - A large post, often used as supporting architecture.