Type Ibn supernovae (SNe) are the interacting class which shows narrow He emission lines (~ 2000 km/sec) due to interaction with dense circumstellar medium (CSM). We present the photometric and spectroscopic studies of a Type Ibn SN~2019uo which is the second SN to show signatures of flash ionisation due to recombination of CSM ionised by the shock breakout flash. SN~2019uo is a faint Type Ibn SN (M$_{v}$\,=\,$-$18.30\,$\pm$\,0.24 mag) with a typical decay rate of 0.1 mag d$^{-1}$ indicating homogeneity among the Type Ibn SN light curves. The color evolution is peculiar which places SN~2019uo between Type Ib and most extreme Type Ibn SNe. The $^{56}$Ni + CSI model best describes the bolometric light curve confirming the signatures of interaction. Typical flash ionisation signatures of He II, C III and N III features are seen in the early spectra. SN~2019uo belongs to the ``P-Cygni" sub-class of Type Ibn SNe and shows faster evolution in velocities as compared to the ``emission" sub-class.