AID - Help; assistance; succor, relief.
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.
HAD - Simple past tense and past participle of have.
HID - Simple past of hide.
OAR - An implement used to propel a boat or a ship in the water, having a flat blade at one end, being rowed from the other end and being normally fastened to the vessel.
RID - Released from an obligation, problem, etc. (usually followed by "of").
ROD - A straight, round stick, shaft, bar, cane, or staff.
RAD - Excellent, short for radical.
ADO - To do; in doing; as, there is nothing ado.
HAIR - A pigmented filament of keratin which grows from a follicle on the skin of humans and other mammals.
HARD - Resistant to pressure.
RAID - A hostile or predatory incursion; an inroad or incursion of mounted men; a sudden and rapid invasion by a cavalry force; a foray.
ROAD - At the venue of the opposing team or competitor.
ARID - Very dry.
RADIO - The technology that allows for the transmission of sound or other signals by modulation of electromagnetic waves.
HOARD - A hidden, secret supply or fund.
HAIRDO - A hairstyle.