This is the 317th most frequent Romanian word.
singur
"Singur" means "alone" or "single" in English.
In this context, 'singur' signifies performing an action individually, without help from others.
Am făcut proiectul singur.
I did the project by myself.
Here, 'singur' is used to indicate being alone, without company.
Sunt singur acasă.
I am alone at home.
Here, 'singurul' (the masculine singular definite articulation of 'singur') means 'the only', describing uniqueness.