1) Spot the word in each group of four that doesn't fit with the others. 1. nail bed, lunula, stiletto, matrix. 4. fifth little piggy, thumb, hallux, second toe. 2. dermatitis, cracked heels, ingrown nails, arrow head 5. callous, heel, back, nail root. 3. ankle, palm, finger, index. 6. ballerina, onychomycosis, edge, flare.

Here are the words that don't fit in each group: 1. **stiletto** - It is a type of shoe, while the others (nail bed, lunula, matrix) are related to nails. 2. **arrow head** - The other terms (dermatitis, cracked heels, ingrown nails) are related to skin or nail conditions. 3. **palm** - The other terms (ankle, finger, index) are body parts related to extremities (limbs). 4. **fifth little piggy** - While the others (thumb, hallux, second toe) are specific terms for fingers and toes, "fifth little piggy" is a playful reference from the nursery rhyme. 5. **back** - The other terms (callous, heel, nail root) relate specifically to foot or nail conditions. 6. **ballerina** - The other terms (onychomycosis, edge, flare) refer to conditions or parts related to nails. Feel free to ask if you need further explanations or assistance!