• alastor,
• alastia,
• plastere,
• aleastake,
• kalasiee,
• zlastair,
• slastair,
• wlastair,
• qlastair,
• akastair,
• apastair,
• aoastair,
• alzstair,
• alsstair,
• alwstair,
• alqstair,
• alaatair,
• alaztair,
• allastair,
• Alistair

The adjective form of the name "Alastair" is "Alastairian". However, this term is not commonly used and may not be widely recognized.

The plural form of the word "Alastair" is "Alastairs".

The singular form of the word "Alastair" is still "Alastair". It does not change when referring to a singular entity.