MOP - An implement for washing floors, or the like, made of a piece of cloth, or a collection of thrums, or coarse yarn, fastened to a handle.
POP - A loud, sharp sound as of a cork coming out of a bottle.
POT - A vessel used for cooking or storing food.
PRO - An advantage of something, especially when contrasted with its disadvantages (cons).
ROT - To suffer decomposition due to biological action, especially by fungi or bacteria.
TOP - That part of an object furthest away in the opposite direction from that in which an unsupported object would fall.
OPT - To choose; to select.
PORT - A place on the coast at which ships can shelter, or dock to load and unload cargo or passengers.
PROM - A promenade concert.
PROP - An object placed against or under another, to support it; anything that supports.
ROMP - To play about roughly, energetically or boisterously.
POMP - Show of magnificence; parade; display; power.
TROMP - To tread heavily, especially to crush underfoot.
PROMPT - Ready, willing (to act).