✅ Base refers to the bottom part, which usually is a key part of a support structure. Base can also refer to the most fundamental part of something (the base of the mountain; the base of an argument).

✅ Nadir refers to the lowest or deepest point (The nadir of his career came when he lost out on an award).

✅ Both of these words refer to a point from which something grows or rises.

✅ However, nadir suggests a low point and is often negative, whereas base suggests something strong that can be built up from.

✅ Fuel means to supply something with food, nourishment, or something else that keeps it going (Anger fueled my outburst; I fueled myself with a protein-rich breakfast).

✅ Feed means to supply something with nourishment (Dry twigs fed the fire; Feed children a balanced diet).

✅ These words can often be used interchangeably. Both mean to provide something that is necessary so that a person or action can continue.

✅ Fill means to extend or be present throughout (The smell of fresh bread filled the room).

✅ Permeate means to saturate and become spread throughout something (Happiness permeated everything she wrote).

✅ Both of these words refer to a thing, such as a smell or mood, becoming tangible or present in every part of something.

✅ Permeate is a fancier, more formal word than fill.