Connotations are related to the nuances of words, providing certain emotional/imaginative implications or associations (e.g. emotive). Euphemisms can often be considered a way around negative connotations (e.g. we say that someone 'passed away' rather than died). For example, referring to someone as a 'gentleman' or 'lady' has connotations of civility; the terms 'man' or 'woman' have much more neutral meanings. One common phrase which makes use connotations is, 'A house is not a home.' While the denoted meaning of house and home within a dictionary can often be the same, the word 'home' carries with it connotations of comfort, security, belonging, etc... When you think of connotations, think of the associated images that come into your mind when a certain word pops up (compare the term 'civilian deaths' with 'civilian casualties'; which one evokes stronger emotions?) You may also want to check out terms such as 'political correctness' to get further examples of how and why connotations are used.