。
She was utterly alone.
Literal
[topic-は] completely lonely was.
孤独 ('loneliness, solitude') is a Sino-Japanese noun-adjective with weighty literary resonance — the kind of word that appears in poetry, philosophy, novels. The compound is 孤 ('alone, isolated') + 独 ('alone, single') — both characters individually mean 'alone,' so the compound is doubly emphatic. Distinct from 一人 ('alone, by oneself'), which is matter-of-factly numerical, 孤独 carries the inner experience of isolation. まったく + 孤独 = 'completely alone' in the existential sense, not just the spatial.