“GRANDAD” is a valid word. — 10 points Scrabble

and
dadan informal term for a father; probably derived from baby talk
ranmove fast by using one's feet, with one foot off the ground at any given time
adda condition (mostly in boys) characterized by behavioral and learning disorders
anamother of the ancient Irish gods; sometimes identified with Danu
raga small piece of cloth or paper
nagsomeone (especially a woman) who annoys people by constantly finding fault
rada unit of absorbed ionizing radiation equal to 100 ergs per gram of irradiated material
dag10 grams
ganseparate the seeds from (cotton) with a cotton gin
garprimitive predaceous North American fish covered with hard scales and having long jaws with needlelike teeth
agatitle for a civil or military leader (especially in Turkey)
gadan anxiety disorder characterized by chronic free-floating anxiety and such symptoms as tension or sweating or trembling or lightheadedness or irritability etc that has lasted for more than six months

anan associate degree in nursing
naa silvery soft waxy metallic element of the alkali metal group; occurs abundantly in natural compounds (especially in salt water); burns with a yellow flame and reacts violently in water; occurs in sea water and in the mineral halite (rock salt)
ada public promotion of some product or service
ara colorless and odorless inert gas; one of the six inert gases; comprises approximately 1% of the earth's atmosphere
aaa dry form of lava resembling clinkers
aga soft white precious univalent metallic element having the highest electrical and thermal conductivity of any metal; occurs in argentite and in free form; used in coins and jewelry and tableware and photography

GRANDAD