ELF - A mythical, supernatural being resembling but seen as distinct from humans.
FIT - Suitable, proper.
FLU - Influenza.
LET - To allow to, not to prevent (+ infinitive, but usually without to).
LIE - To be in a horizontal position.
LIT - Little.
TIE - A necktie (item of clothing consisting of a strip of cloth tied around the neck).
TIL - Until, till.
FILE - A collection of papers collated and archived together.
FUEL - Substance consumed to provide energy through combustion, or through chemical or nuclear reaction.
LEFT - The opposite of right; toward the west when one is facing north.
LIFE - The state that follows birth, and precedes death; the state of being alive and living.
LIFT - Air.
TILE - A regularly-shaped slab of clay or other material, affixed to cover or decorate a surface, as in a roof-tile, glazed tile, stove tile, etc.
LITE - Light in composition, notably low in fat, calories etc.:.
LUTE - A fretted stringed instrument, similar to a guitar, having a bowl-shaped body or soundbox.
FLUE - A pipe or duct that carries gaseous combustion products away from the point of combustion (such as a furnace).
FLUTE - A woodwind instrument consisting of a metal, wood or bamboo tube with a row of circular holes and played by blowing across a hole in the side of one end or through a narrow channel at one end against a sharp edge, while covering none, some or all of the holes with the fingers to vary the note played.
FILET - A narrow strip of ribbon, material or meat.
FUTILE - Incapable of producing results; useless; not successful; not worth attempting.