1. (n) a cheaply owned and operated nail salon.
2. (adj.) an ecstatic individual.
3. (n) an act of sexual intercourse that yielded pleasing results.
For definitions 2 and 3, increased repetition of the word happy or nail in succession of one another emphasizes their respective pleasantness. The repetition does not have to be in the correct order and either word can be omitted entirely as long as the amount of words in the phrase is equal to 2 or more.
Ex: Happy nail nail; happy happy happy; nail happy happy.
1. I got Sarah a gift card to the happy nail.
2. Jon was a happy nail after opening his birthday present.
3. That hot date last night ended in a happy happy nail.