CON - To study, especially in order to gain knowledge of.
COP - To (be forced to) take; to receive; to shoulder; to bear, especially blame or punishment for a particular instance of wrongdoing.
CUP - A concave vessel for drinking from, usually made of opaque material (as opposed to a glass).
COO - The murmuring sound made by a dove or pigeon.
PUN - To beat; strike with force; ram; pound, as in a mortar; reduce to powder.
COOP - A pen or enclosure for birds.
UPON - Being above and in contact with another.
COUP - A quick, brilliant, and highly successful act; a triumph.
COUPON - A certificate of interest due, printed at the bottom of transferable bonds (state, railroad, etc.), given for a term of years, designed to be cut off and presented for payment when the interest is due; an interest warrant.