In homeopathic understanding, chronic diseases are those that are deep-seated, long-lasting, and tend to progress over time if not treated appropriately. Let's examine each option:
\begin{itemize}
\item One-sided diseases: These are conditions where only a few symptoms are prominently expressed, often making them challenging to treat and frequently of a chronic nature.
\item Indisposition: This term generally refers to a temporary state of mild illness or feeling unwell. It is usually acute and self-limiting or resolves quickly with simple measures or a short course of treatment. It does not typically fall under the classification of a chronic disease.
\item Alternating diseases: These are characterized by the periodic alternation of different sets of symptoms or pathological states. While the individual episodes might be acute, the underlying tendency to alternate can be a chronic manifestation.
\item Mental and emotional diseases: These conditions, affecting the psyche and emotional well-being, are often chronic and require long-term management in homeopathy.
\end{itemize}
Therefore, indisposition does not belong to the class of chronic diseases as it describes a transient state of illness, unlike one-sided, alternating, and mental/emotional diseases which can have a chronic underlying nature.