league
In Italian, the word 'lega' is used to refer to a league, which is an association of individuals, countries, or groups with a common interest or purpose. It can also refer to a sports league, just like in English. For example, 'La lega calcio' means 'The football league'.
The alloy is very resistant
In this context, 'lega' means alloy, referring to a metal made by combining two or more metallic elements.
Tie the knot tighter
In this sentence, 'lega' is used as a verb. It's an imperative form that means 'tie'.
The Northern League is an Italian political party
In this case, 'Lega' refers to 'Lega Nord', an Italian political party. Here it is used as a proper noun.