complex
The Italian word 'complesso' is used to describe something that is complex or complicated. It can refer to a situation, a problem, or an idea that is difficult to understand or solve. It is an adjective and can be used to modify nouns. For example, 'un problema complesso' means 'a complex problem'. The word can also be used as a noun to refer to a group of buildings or a group of people working together, such as 'un complesso residenziale' (a residential complex) or 'un complesso musicale' (a musical ensemble).
The mathematician is solving a complex problem.
In this sentence, 'complesso' is used as an adjective to describe the problem the mathematician is dealing with. In Italian, adjectives usually come after the noun they refer to.
I live in an apartment complex.
Here, 'complesso' is used as a noun to describe a group of buildings that are grouped together because they all are part of the same entity or purpose. This is a common use of 'complesso' in Italian.
The situation is fairly complex.
In this context, 'complesso' is an adjective adding detail to the nature of the situation, suggesting it involves many interconnected or difficult aspects. When referring to a situation, complesso often implies that it is hard to understand or deal with.