Tension revealed by female teacher avoiding motorway (6)
I believe the answer is:
stress
'tension' is the definition.
(synonyms)
'female teacher avoiding motorway' is the wordplay.
'female teacher' becomes 'mistress' (schoolmistress).
'avoiding' indicates named letters should be taken away.
'motorway' becomes 'MI' (resembles M1, English motorway).
'mistress' with 'mi' taken away is 'STRESS'.
'revealed by' is the link.
(Other definitions for stress that I've seen before include "Feeling of pressure" , "nervous tension" , "Tension, pressure" , "'Strain, tension (6)'" , "Force" .)