APP - An application (program), especially a small one designed for a mobile device.
ARE - Second-person singular simple present tense of be.
EAR - The organ of hearing, consisting of the pinna, auditory canal, eardrum, malleus, incus, stapes and cochlea.
ERA - A time period of indeterminate length, generally more than one year.
PAR - By; with.
PEP - To inject with energy and enthusiasm.
PER - For each.
RAP - A sharp blow with something hard.
PAP - Food in the form of a soft paste, often a porridge, especially as given to very young children.
REP - Short form of reputation.
ERR - To make a mistake.
PEAR - An edible fruit produced by the pear tree, similar to an apple but elongated towards the stem.
PREP - Preparation.
RARE - Cooked very lightly, so the meat is still red (in the case of steak or beef in the general sense).
REAR - To raise physically; to lift up; to cause to rise, to elevate.
REAP - To cut with a sickle, scythe, or reaping machine, as grain; to gather, as a harvest, by cutting.
PARE - To remove the outer covering or skin of something with a cutting device, typically a knife.
PAPER - A sheet material used for writing on or printing on (or as a non-waterproof container), usually made by draining cellulose fibres from a suspension in water.
RAPPER - One who, or that which, raps or knocks; specifically, the knocker of a door.