Conjunctions in Hindi grammar, known as संयोजक (sanyojak), are essential for connecting words, phrases, or clauses to give sentences a coherent structure. They help in building meaningful relationships between different elements in a sentence. Common Hindi conjunctions include और (and), या (or), परन्तु (but), जबकि (while), and तथा (as well as). Mastering conjunctions in the Hindi language will enable learners to express complex ideas and thoughts more effectively.