1. let-alone - Adjective
2. let-alone - Verb
3. let-alone - Adverb
4. let-alone - Conjunction
Letting alone.
Source: Webster's dictionarylet alone
leave it as is Source: Internet
leave the young fawn alone Source: Internet
leave the flowers that you see in the park behind Source: Internet
she can't boil potatoes, let alone cook a meal Source: Internet
According to The Simon Wiesenthal Center (in January 2011) "Ukraine has, to the best of our knowledge, never conducted a single investigation of a local Nazi war criminal, let alone prosecuted a Holocaust perpetrator." Source: Internet
Additionally, no earlier source mentions that Helena was born in Britain, let alone that she was a princess. Source: Internet