alone
By oneself, solitary.
Lacking peers who share one's beliefs, experiences, practices, etc.
(obsolete) Apart from, or exclusive of, others.
(obsolete) Mere; consisting of nothing further.
(obsolete) Unique; rare; matchless.
By oneself; apart from, or exclusive of, others; solo.
Without outside help.
Not requiring anything further; merely.
(by extension) Used to emphasize the size or extent of something by selecting a subset.