  We present NGC 6221 as a case study of ``X-ray loud composite galaxies,''
which appear similar to starbursts at optical wavelengths and resemble
traditional active galactic nuclei in X-rays. The net optical spectrum of NGC
6221 is properly characterized as a starburst galaxy, but in X-rays, NGC 6221
is similar to Seyfert 1 galaxies, exhibiting a power-law continuum spectrum, a
broad Fe K alpha line, and continuum variability on timescales of days and
years. High-resolution images reveal that the detected active nucleus is
relatively weak, not only at optical, but also at near-infrared wavelengths. An
obscuring starburst, in which the interstellar gas and dust associated with the
starburst conceal the active nucleus, accounts for these peculiar features. We
demonstrate quantitatively that obscuration by column density N_H = 10^{22}
cm^{-2} combined with relatively weak intrinsic nuclear activity can produce an
optical spectrum characteristic of the surrounding starburst alone. While
optical surveys would not identify the active nuclei that make these galaxies
significant X-ray sources, such galaxies may in fact be important contributors
to the X-ray background.
