Our Preamble says

We the people of India having solemnly resolved to constitute India as sovereign , social ,secular , democratic republic and to secure its citizen

Justice: Social , Economic & Political Liberty of thought , expression , belief , faith and worship, Equality of status and opportunity, Fraternity assuring dignity of individual and unity and integrity of the nation

On this constituent assembly on 26 jan, do hereby adopt , enact and give it to ourselves this constitution.

ये भारतीय संविधान की प्रस्तावना है जिसे भारतीय संविधान की आत्मा कहा गया है

As we see up top that different terms has been used in the preamble like Sovereign, socialist , secular , democratic & republic , we need to understand these term in order to understand our constitutions. Basically these terms are the basic ingredients of our constitution. Let us describe these words briefly.

Sovereign: It means India has power to take its decision on its own in every aspect of its affairs no body can stop her from making her own decision and no body can supersede its power . though India became a member of commonwealth in 1949 and England being the head of commonwealth country doesn’t make and difference on its sovereignty , likewise even if India is a member of UNO but she is free to take its own decision.

Socialist: India will promote socialist theory but in its democratic form not the form that describes Marx theory of socialism where resources are nationalized and a complete prohibition of private property or business. India has a mixed economy and both the private and govt form of business exist here but resources will be distributed equally in democratic form . so here democratic form of socialism exists.