Round 1
symbols for minutes or feet (6)
things made of several parts (10)
$\sum_{n=1}^{\infty}(\frac{1}{2})^n$ (3)
Round 2
Italian snow, reversed (4)
supporting pillars (7)
at that time (4)
strange (3)
Round 3
occasional (3)
how one powers a single scull (4)
after that (4)
flat and smooth (4)
Round 4
essentials for living (4)
alike (4)
an authoritative command (5)
Round 5
turning over in the air (4)
highest quality (5)
homophone for the most popular flower (4)
Round 6
dog's feet, reversed (4)
posts holding up a structure, w/o vowels (5)
solution count to $\sqrt{3^2}$ (3)
Frank Lentini's leg count (5)
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EDIT: Any word that is found cannot proceed to the next round.
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The answer is a word that names a quality necessary to complete this puzzle.
Text version:
A,K,P,S,E,E,R,D,E,C
N,E,S,R,S,P,S,N,O,M
F,U,L,L,I,O,C,M,D,I
S,R,N,O,D,M,P,N,W,E
W,W,E,O,V,O,E,H,I,E
S,N,M,H,S,T,W,S,P,E
I,M,H,I,O,O,A,N,T,D
E,V,T,L,R,E,N,T,O,E
C,E,D,L,D,C,R,E,E,E
S,E,P,E,R,M,G,O,O,P