APE - A primate of the clade Hominoidea, generally larger than monkeys and distinguished from them by having no tail.
APP - An application (program), especially a small one designed for a mobile device.
PAR - By; with.
PEA - A plant, member of the legume (Fabaceae) family.
PEP - To inject with energy and enthusiasm.
PER - For each.
PUP - A young dog, wolf, fox, seal, shark and some other animals.
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.
RUE - Repentance, regret.
PEAR - An edible fruit produced by the pear tree, similar to an apple but elongated towards the stem.
PREP - Preparation.
PURE - Free of flaws or imperfections; unsullied.
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.
UPPER - That which is higher, contrasted with the lower.
PAUPER - One who is extremely poor.