Nothing is stable in languages. Both words and their meanings change, just as is the casc with other phenomena in the world. Yet there is a gene- ral concept that forms are more stable than meanings It is this change that causes Some difficulties that one faces in the study of meaning. Purgess (1981: 107) states that some reasons for this change are essentially linguistic, some others Psychological, historical, or Social. The English word 'Towi', for instance, was once used to refer to any kind of bird, but now it only means a chicken. The word 'cat' on the other hand, which was used to mean the known domestic animal, acquired other denotations and encompassed other animals belonging to the feline family, e.g. lion, tiger ete. It is also used derogatively to mean a malicious woman .