“GADWALL” is a valid word. — 12 points Scrabble

gladany of numerous plants of the genus Gladiolus native chiefly to tropical and South Africa having sword-shaped leaves and one-sided spikes of brightly colored funnel-shaped flowers; widely cultivated
wallan architectural partition with a height and length greater than its thickness; used to divide or enclose an area or to support another structure
galaa gay festivity
gallan open sore on the back of a horse caused by ill-fitting or badly adjusted saddle
algaprimitive chlorophyll-containing mainly aquatic eukaryotic organisms lacking true stems and roots and leaves

allquantifier; used with either mass or count nouns to indicate the whole number or amount of or every one of a class
lawthe collection of rules imposed by authority
lada boy or man
galUnited States liquid unit equal to 4 quarts or 3.785 liters
wada small mass of soft material
lagthe act of slowing down or falling behind
dala metric unit of volume or capacity equal to 10 liters
dag10 grams
waga witty amusing person who makes jokes
agatitle for a civil or military leader (especially in Turkey)
alaa flat wing-shaped process or winglike part of an organism
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
awa
awla pointed tool for marking surfaces or for punching small holes
dawcommon black-and-grey Eurasian bird noted for thievery
aal

laa white soft metallic element that tarnishes readily; occurs in rare earth minerals and is usually classified as a rare earth
aw
ala silvery ductile metallic element found primarily in bauxite
ada public promotion of some product or service
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

GADWALL