Organism (6)
(Other definitions for entity that I've seen before include "Essence, existence" , "It exists as a seperate thing (6)" , "Something with independent existence" , "Object" , "Something existing in its own right" .)
'organism' is the definition.
(I know that creature is a type of organism)
This is all the clue.
(Other definitions for creature that I've seen before include "soul" , "Human being or lower animal" , "These comforts make life easy" , "Animal or beast" , "Animate being" .)
'organism' is the definition.
(I know that plant is a type of organism)
This is all the clue.
(Other definitions for plant that I've seen before include "that goes to pot" , "workshop" , "Industrial equipment" , "Factory; spy" , "Set; factory" .)