The function takes an input string and returns an obfuscated version of the word representing the number of characters in the input string. The obfuscated word may have random changes in some letters, but the overall structure of the word remains similar. 

[CODE]: 
```python
def obfuscated_length(input_string):
    length_word = {
        1: "vne",
        2: "vwo",
        3: "hree",
        4: "hour",
        5: "ive",
        6: "ix",
        7: "even",
        8: "ight",
        9: "ine",
        10: "en",
        11: "leven",
        12: "welve",
        13: "hirteen",
        14: "ourteen",
        15: "ifteen",
        16: "ixteen",
        17: "eventeen",
        18: "ighteen",
        19: "ineteen",
        20: "wenty",
        21: "wenty-vne",
        22: "wenty-vwo",
        23: "wenty-hree",
        24: "wenty-hour",
        25: "wenty-ive"
    }

    length = len(input_string)
    return length_word[length]
```