To put in a lot of effort or hard work, often in trying circumstances.

बहुत कठिनाई में खूब मेहनत करना।

English Usage: He had to sweat his guts out to finish the project on time.

Hindi Usage: उसे समय पर परियोजना पूरी करने के लिए अपना खून-पसीना बहाना पड़ा।