Demonstratives as Adjectives:
E.g. hic amïcus = this friend; ille amïcus = that friend
Ille and hic can mean "the former" and "the latter".
Ille can mean "the famous".
Iste can be translated as "that...of your's" with a disparaging air
iste amïcus (loosely translated) = that obnoxious friend of your's
Demonstratives as Pronouns:
E.g. hic = this man; illa = that woman; hoc = this thing