Medic with unopened tablet in practice (5)
I believe the answer is:
drill
'in practice' is the definition.
(I've seen this before)
'medic with unopened tablet' is the wordplay.
'medic' becomes 'dr' (abbreviation for doctor).
'with' says to put letters next to each other.
'unopened' means to remove the first letter (without opening letter).
'tablet' becomes 'pill' (synonyms).
'pill' with its first letter removed is 'ill'.
'dr'+'ill'='DRILL'
(Other definitions for drill that I've seen before include "Tool; fabric; bore" , "Put a hole in" , "Hole-making tool" , "(Correct) procedure" , "strong twilled cotton" .)