Alone

1. Quite by one's self; apart from, or exclusive of, others; single; solitary; -- applied to a person or thing.
2. Of or by itself; by themselves; without any thing more or any one else; without a sharer; only.
3. Sole; only; exclusive.
4. Hence; Unique; rare; matchless.
To let alone or To leave alone ,
to abstain from interfering with or molesting; to suffer to remain in its present state.

1. Solely; simply; exclusively.