The term 'Only Kidding!' is an expression used to indicate that something said was not meant to be taken seriously. It is often used as a joke or to lighten the mood after a serious statement. The crossword solutions for this term are 'NOT' (3 letters) and 'IWAS' (4 letters). 'Not' is a negative adverb used to indicate that something is not true or does not exist, while 'Iwas' is a contraction of the phrase 'I was, ' which is used to indicate past tense.