difference between paigambar, nabi and rasool

Walaikum assalam w arahmatullah,

Paighambar is an urdu word which am not very sure if it better translates as Rasul or nabi. I'd leave that for someone else to clarify.

Basically you are asking the difference between a nabi and a rasul, ie a prophet and a messenger.

taken from seekersguidance Q&A section:
http://seekersguidance.org/ans-blog/2012/03/28/is-our-master-muhammad-allah-bless-him-and-give-him-peace-the-last-messenger-or-the-last-prophet/

The Difference between a Prophet (nabi) and a Messenger (rasul)

In his commentary on the famous text of Sunni creed Jawhara al-Tawhid, Imam al-Bajuri provides useful definitions of the terms you asked about in your first question.

He defines a prophet (nabi) as a human being who is �free from all repulsive qualities, [and] given a revealed law that he enacts, even if he was not commanded to spread it.�

In contrast, Imam al-Bajuri defines a messenger (rasul) as someone who has the qualities of a prophet �but with the additional stipulation [of him being] commanded to spread [his message].�

In other words, the main difference between a prophet and a messenger pertains to spreading the revealed message (tabligh): messengers only include those commanded to spread the revelation they receive, while prophets include both those who received that command and those who didn�t. This means, as Imam al-Bajuri explains, that �every messenger is a prophet, but not vice-versa.�

[Bajuri, Tuhfat al-Murid `ala Jawharat at-Tawhid]