What do you mean by faith?

KALIMAH TAYYIBAH

لآ إله إلّا الله محمّد رّسول الله 

NONE IS WORTHY OF WORSHIP BUT ALLAH

MUHAMMAD IS THE MESSENGER OF ALLAH. 

What is Iman?

The  literal meaning of Iman is to believe in someone’s words relying solely on his authority. In religious terms, it implies belief in the Unseen relying solely on the authority of the Messenger of Allah Subhanhu wa Ta’ala. 

Iman has more than seventy branches. The superiormost or the highest in level is saying-just saying the Kalimah Tayyiba which is the La ilaha illallah- which means "there is no diety but ALLAH only or there is no worthy of worship except Allah Subhanahu wa Ta'ala.

If there is a superior, there is also an inferior-the most inferior branch of Iman that a believer has is the removal of an obstacle from the way or a street or anywhere. Which means whenever a person attempted to remove an obstacle or a small garbage from a way or a street, it's a sign that the person has his inferior faith. And Haya which means the shyness is a branch of faith too.

The hadith of this lesson is as follows: 

Kalimah Tayyibah 001 

Abu Hurairah Radiyallahu ‘anhu narrates that Rasulullah Sallallahu ‘alaihi wasaallam said: “Iman (faith) has more than seventy branches; the superiormost one is saying of La ilaha illallah (There is none worthy of worship except Allah); and the inferior most is the removal of an obstacle from the way; and Haya is a branch of Iman.” (Muslim) 
NOTE: The essence of Haya is that it restrains a man from evil and prevents a man from neglecting the obligations that he owes to others. (Riyad-ud-Salihin)