  We present ground-based optical transmission spectroscopy of the low-density
hot Jupiter WASP-88b covering the wavelength range 4413-8333 {\AA} with the
FORS2 spectrograph on the Very Large Telescope. The FORS2 white light curves
exhibit a significant time-correlated noise which we model using a Gaussian
Process and remove as a wavelength-independent component from the spectroscopic
light curves. We analyse complementary photometric observations from the
Transiting Exoplanet Survey Satellite and refine the system properties and
ephemeris. We find a featureless transmission spectrum with increased
absorption towards shorter wavelengths. We perform an atmospheric retrieval
analysis with the AURA code, finding tentative evidence for haze in the upper
atmospheric layers and a lower likelihood for a dense cloud deck. Whilst our
retrieval analysis results point toward clouds and hazes, further evidence is
needed to definitively reject a clear-sky scenario.
