express + To state or show what you think or how you feel
expression + act of making your thoughts and feelings known
press + To push something against something else
depress + To make someone feel sad or depressed
depression + medical condition in which a person's sadness stops him/her from living his/her life normally
impress + To make an emotional or cognitive impact upon
impressive + Causing admiration or respect; big, grand, expensive etc
pressure + the force/weight when pressing against a thing
impression + effect or feeling resulting from an experience