  We study implications of the four-fermion semileptonic operators at the
low-energy and at electroweak (EW) scale in the framework of Standard Model
Effective Field Theory (SMEFT). We show how the renormalization group (RG)
running effects can play an important role in probing the \emph{generic flavour
structure} of such operators. It is shown that at the 1-loop level, through RG
running, depending upon the flavour structure, these operators can give rise to
sizable effects at low energy in the electroweak precision (EWP) observables,
the leptonic, quark, as well as the $Z$ boson flavour violating decays. To this
end, we isolate the phenomenological relevant terms in the full anomalous
dimension matrices (ADMs) and discuss the impact of the QED+QCD running in the
Weak effective field theory (WET) and the SMEFT running due to gauge and Yukawa
interactions on the dim-4 and dim-6 operators at the low energy. Considering
all the relevant processes, we derive lower bounds on the new physics (NP)
scale $\Lambda$ for each semileptonic operator, keeping a generic flavour
structure. In addition, we also report the allowed ranges for the Wilson
coefficients at a fixed value of $\Lambda=3$ TeV.
