What does the word "too" imply?

The word "too" implies an excessive degree or amount of something that surpasses a desired or acceptable limit. When used, it often conveys a sense of negativity or an undesirable quality due to this excess. For example, if someone says "It's too hot," they are indicating that the heat exceeds a comfortable level. The other options do not align with this meaning; "not enough" suggests a deficiency, "just right" implies a perfect balance, and "moderately" indicates a measured or acceptable level—all of which do not capture the connotation of excess that "too" conveys. Hence, the understanding of "too" as meaning excessively is accurate and aligns with its usage in the English language.