Example : The lone doctor in the entire county.
A lonesome pine.
An only child.
The sole heir.
The sole example.
A solitary instance of cowardice.
A solitary speck in the sky.

Synonyms : lone, only, sole, solitary

Example : Felt sad and lonely.
The loneliest night of the week.
Lonesome when her husband is away.
Spent a lonesome hour in the bar.

Synonyms : lonely