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

innerlocated inward
finer(comparative of `fine') greater in quality or excellence
inferreason by deduction; establish by deduction
renina proteolytic enzyme secreted by the kidneys; catalyzes the formation of angiotensin and thus affects blood pressure

finemoney extracted as a penalty
firethe event of something burning (often destructive)
ninethe cardinal number that is the sum of eight and one
fernany of numerous flowerless and seedless vascular plants having true roots from a rhizome and fronds that uncurl upward; reproduce by spores
reinone of a pair of long straps (usually connected to the bit or the headpiece) used to control a horse
rifemost frequent or common
reif
firn
neif

inna hotel providing overnight lodging for travelers
finthe cardinal number that is the sum of four and one
rin
ref(sports) the chief official (as in boxing or American football) who is expected to ensure fair play
firnonresinous wood of a fir tree
rei
fer
fie
fen100 fen equal 1 yuan in China
irea strong emotion; a feeling that is oriented toward some real or supposed grievance
ernbulky greyish-brown eagle with a short wedge-shaped white tail; of Europe and Greenland
rif

ina unit of length equal to one twelfth of a foot
if
era trivalent metallic element of the rare earth group; occurs with yttrium
rea rare heavy polyvalent metallic element that resembles manganese chemically and is used in some alloys; is obtained as a by-product in refining molybdenum
enhalf the width of an em
nea colorless odorless gaseous element that give a red glow in a vacuum tube; one of the six inert gasses; occurs in the air in small amounts
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FINNIER