Cooperative, Charitable, Constructive. :-)
"Conceptualized" is the word that starts with a "c" and means to form an idea.
A word that starts with C and means "accident prone" is "clumsy".
Carnation.
capitulate
cram
crismatic
It could be the word cheap
Cool
Cavort.
complaisantcondescendingconsiderate
condense
cadaverous