The Oxford Thesaurus An A-Z Dictionary of Synonyms - solitaryadj.

1) lone, single, sole, individual; unattended, solo, companionless, friendless, lonesome, lonely, unsocial, cloistered, secluded, reclusive, separate, eremitic(al) , hermitic(al) , remote, withdrawn, distant, out-of-the-way, unfrequented, desolate: There is not a solitary exception to the rule. Flora's solitary style of living allows her to concentrate on her writing. There is a solitary little inn where we go for weekends. --n. 2) solitary confinement: The prisoner has been in solitary for striking a guard.