While the dictionary says that "coward" can be used as an adjective, it's very unusual to use it that way. Most of us will use "coward" as a noun. A passage from Edmund Spenser's epic poem THE FAERIE QUEENE reads thus: "And evermore that craven coward Knight,..." But that poem was published in the 1590s!

Cowardly is the adjective, so it is correct in this sentence. Coward is a noun, so to use it in this sentence you would have to change it to: I am too much of a coward to tell her anything.

hi Diamond, just to let you know that the word "coward" is a noun and "cowardly" is an adjective, and to answer your question if you can use them interchangeably, the answer is no. In this sentence " I'm too cowardly to tell her anything." the person is trying to describe himself/herself here as "cowardly" so it is only proper to use this word as an adjective. I hope i have helped you in some way.

coward = noun cowardly = adjective he he

ı am too coward to...