• maleboat,
• nailboat,
• kailboat,
• jailboat,
• mzilboat,
• msilboat,
• mwilboat,
• mqilboat,
• maulboat,
• majlboat,
• maklboat,
• maolboat,
• ma9lboat,
• ma8lboat,
• maikboat,
• maipboat,
• mailboast,
• mialboat,
• maiilboat,
• maillboat

• male body,
• mail boat.

The adjective form of the word "mailboat" is "mailboat". The word functions as both a noun and an adjective, describing a boat used for carrying mail.

The plural form of "mailboat" is "mailboats".

The singular form of the word "mailboat" is "mailboat". Since it already refers to a single boat used for mail transport, the singular and plural forms are the same.