What is the dafination of abstract noun

An abstract noun is a noun that does not actually take shape in the real world. For example, the word “logic” is a noun, but one cannot hold logic or look at logic. One can look at a logic book or a logical sentence, but one cannot look at logic itself.

Explanation:

the correct answer is:   [d]:

              →       " fond of fighting " .

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      best wishes!

a. is the correct answer