Fair Isle - A type of design used in knitwear named after a Shetland island. History has it that a 16th century Spanish Armada galleon was wrecked and the sailors rescued from the vessel wore garments bearing Moorish designs which the Shetland islanders copied. Fair Isle knitwear is hand knitted wool with horizontal, coloured bands with naive or folky patterns and designs.
Felt - A fabric formed without weaving, using the natural tendency of the fibres of wool or rabbit fur to interface and cling together into a mat-like texture. Felt is the oldest fabric known to humankind.
Fitch - The fur of the european polecat.
Frog pocket - A form of cross pocket in the trousers with the seam end opened vertically a few inches so it is easier to get your hand in.
Fugly - Very ugly or unattractive, but in a cool way