An abstract noun is known to be a class of noun that refers to something intangible. These nouns actually refer to certain concepts such as an emotion, a feeling, a quality, or an idea which are not concrete and can't be touched.
These nouns are seen as a word that names something that one cannot see, touch, taste, hear, or smell. This means that they actually nouns that cannot be perceived with the five senses.
Efficient means someone who is working in a well-organized way and plans things well. So think of what a character would do being "well-organized" "well-planned" ...etc.
after restoration of monarch, when the freedom of nonconformist was curtailed, Bunyan was arrested and spent the next twelve years in jail as he refused to give up preaching
