my proposal is the following completion (in a chain-of-thought compatible manner):

'On the one hand, courage is a concept which has a positive connotation. It can be defined as the propensity to take risks appropriately. The propensity to take risks is a neutral concept. The dual concept of the propensity to take risks is the propensity to avoid risks. It is also a neutral concept. The contrary of courage is a negative concept, that can be defined as the propensity to avoid risks inappropriately. The concept of cowardice is a negative concept that fits this definition. Hence, cowardice is the contrary of courage.'