0 a creature from a planet other than Earth -- alieno, -a
1 a person who lives in a country but is not a citizen -- cittadino straniero, cittadina straniera
a resident alien un cittadino straniero
3 relating to creatures from another planet -- alieno, extraterrestre
an alien spacecraft una nave spaziale extraterrestre
4 strange and very different from what you are used to; foreign -- straniero
They found themselves in an alien environment
alien customs.
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
Possiamo completarlo passo dopo passo, indipendentemente dalla lunghezza della strada, e non può essere completato, per quanto breve sia la strada, se non segni nemmeno la tua impronta.