using itemize defined as newenvironment gives errors: missing item / missing list environment

Question

I try to define a newenvironment for a new way of itemizing, but when I use the newenvironment (named itemize-compact) I get the error 'missing item' (within tabular) or 'missing list environment'.

(FYI: in the end I would like to use the newenvironment to define a list with less space between, above, under, and left of the items, using functions as labelsep and parsep, to be used within tabular.)

Below a somewhat MWE with both the use of the newly defined itemize in a tabular and in general text. I've enclosed a picture of its result.

Thank you so much in advance!

\documentclass{book}
\usepackage{array,enumitem}  

\newenvironment{itemize-compact}%
  {\begin{itemize}
    %no alternative properties included yet, because this already gives the errors stated below
    \end{itemize}}

\begin{document}

\begin{tabular}{|m{5cm}|m{10cm}|}
\hline
Text    & 
\begin{itemize}
\item itemize within tabular works fine
\end{itemize}
\\
\hline
\end{tabular}

\begin{tabular}{|m{5cm}|m{10cm}|}
\hline
Text    & 
\begin{itemize-compact}
\item the newly defined environment `itemize-compact' within tabular gives the error: *there's something wrong, perhaps a missing item*
\end{itemize-compact}
\\
\hline
\end{tabular}

\begin{itemize}
\item itemize works fine
\end{itemize}

\begin{itemize-compact}
\item the newly defined environment `itemize-compact' gives the error: *lonely item, perhaps a missing list environment*
\end{itemize-compact}

\end{document}