cytoarchitectonics vs. cytoarchitecture
compressibility vs. squeezability
compressibility vs. sponginess
colorlessness vs. colourlessness
cylindricality vs. cylindricalness
configuration vs. constellation
contemporaneity vs. contemporaneousness
contemporaneousness vs. modernism
ceaselessness vs. continuousness
continuousness vs. incessantness
capaciousness vs. spaciousness
capaciousness vs. commodiousness
countlessness vs. innumerableness
calcitonin vs. thyrocalcitonin
chondriosome vs. mitochondrion
comprehensiveness vs. largeness
comprehensiveness vs. fullness
chromaesthesia vs. chromesthesia
crystallisation vs. crystallization