Short answers, pulled from the story.
The five hindrances in Buddhism are sensory desire, ill-will, sloth-and-torpor, restlessness-and-worry, and doubt. These mental factors block progress in meditation and daily life according to Theravada teachers.
Gil Fronsdal explains that the Pali term nīvaraņa means covering which obscures the clarity of our mind and ability to be mindful. Rhys Davids notes this term refers to an obstacle or hindrance only in the ethical sense within Buddhist texts.
The Buddha compares sensual desire to clear reflection in water mixed with lac turmeric and dyes while ill will resembles boiling water that cannot reflect anything clearly. Sloth-and-torpor appears like water covered with plants and algae whereas restlessness-and-worry looks like wind-churned water that never settles. Doubt presents itself as water that is turbid unsettled muddy and placed in the dark.
The Samyutta Nikaya contains several discourses including SN 46.37 that record specific relationships between these mental factors. The Satipatthana Sutta proclaims methods for gaining insight into and overcoming the Five Hindrances according to Anālayo.
Afflictive obstructions arise from defilements such as anger envy and ignorance while cognitive obstructions stem from misconceptions about reality like reifying imaginary phenomena. Only advanced bodhisattvas can overcome cognitive obstructions attaining complete understanding of emptiness and compassion whereas Buddhas alone transcend both types achieving complete insight into all objects of knowledge.