  The Advanced LIGO and Virgo gravitational wave observatories detected a
signal on 2019 August 14 during their third observing run, named GW190814. A
large number of electromagnetic facilities conducted follow-up campaigns in the
search for a possible counterpart to the gravitational wave event, which was
made especially promising given the early source classification of a neutron
star-black hole merger.We present the results of the GW follow-up campaign
taken with the wide-field optical telescope MeerLICHT, located at the South
African Astronomical Observatory Sutherland site. We use our results to
constrain possible kilonova models. MeerLICHT observed more than 95% of the
probability localisation each night for over a week in three optical bands
(u,q,i) with our initial observations beginning almost 2 hours after the GW
detection. We describe the search for new transients in MeerLICHT data and
investigate how our limiting magnitudes can be used to constrain an
AT2017gfo-like kilonova. A single new transient was found in our analysis of
MeerLICHT data, which we exclude from being the electromagnetic counterpart to
GW190814 due to the existence of a spatially unresolved source at the
transient's coordinates in archival data. Using our limiting magnitudes, the
confidence with which we can exclude the presence of an AT2017gfo-like kilonova
at the distance of GW190814 was low ($<10^{-4}$).
