Synonyms for alone

Most common

1. Unaccompanied — by oneself, solitary. Not involved in a romantic relationship

2. Lonely

lonely, solitary, lone, companionless rare

3. Isolated — lacking peers who share one's beliefs, experiences, practices, etc

4. Unique — unique; rare; matchless

Other

1. Solely — focus adverb, typically modifying a noun and occurring immediately after it. Not permitting anything further…

2. Single-handed — without outside help

3. Solo — by oneself; apart from, or exclusive of, others; solo

adj. 1
By oneself, solitary. Not involved in a romantic relationship.
adj. 2
Lacking peers who share one's beliefs, experiences, practices, etc.
Senator Craddock wants to abolish the estate tax, and she's not alone.
adv. 1
By oneself; apart from, or exclusive of, others; solo.
adv. 2
Without outside help.
The job was too hard for me to do alone.

Word family: aloneness
Phrases: let alone leave alone go it alone leave it alone leave things alone let it alone let things alone walk alone

available Please inform me what options are available to me.
unaccompanied Unaccompanied minors are not permitted on this flight.
unattached My coach asked me if I was "unattached" and I didn't understand so I said yes.
lonely Left to himself, the child would feel very lonely.
solitary Bruno spends his birthday in solitary confinement.
isolated Sami lived on an isolated islands for many months.

Use in printed books, per decade from 1850 to 2019.

3 letters: odd¹
4 letters: just¹, only², very², pure¹, solo², sole¹, bare¹, mere¹, lone¹
5 letters: pyore
6 letters: single², simple², unique², merely², lonely², solely³, purely², singly²
7 letters: azygous
8 letters: entirely⁴, isolated⁴, solitary⁴, singular³, deserted³, forsaken³, peerless²
9 letters: available⁴, exclusive³, unmatched², matchless, unequaled³, nonpareil
10 letters: unattached³, unassisted⁴, unequalled, solitarily
11 letters: exclusively⁴, unpartnered
12 letters: unparalleled⁴, incomparable⁵
13 letters: unaccompanied⁵, unparallelled, companionless

The small number after each word is its number of syllables (only² = 2 syllables).