The function f(x) takes a string input and returns the length of that string as a word.

[CODE]:
```python
def word_length(input_string):
    length_words = {
        1: "one",
        2: "two",
        3: "three",
        4: "four",
        5: "five",
        6: "six",
        7: "seven",
        8: "eight",
        9: "nine",
        10: "ten"
    }

    return length_words[len(input_string)]
```

Let's run a couple more tests to confirm this.

COMMAND: PYTHON(./temp/function.py "example")
COMMAND: PYTHON(./temp/function.py "test")