How one can define the FORCE, if he is a MSc student?
Force must be understood as an interaction
Pretty much depends on what field you are studying.
It might be defined in terms of the Lagrangian or Hamiltonian of motion if you’re studying classical mechanics.
In particle physics, it is the interaction resulting due to exchange of Gauge bosons such as W and Z bosons.
However, the old school definition of rate of change of momentum isn’t technically incorrect too.