Under- (too little, below)
Under-
Too little; or below.
The rice was undercooked, so we boiled it longer.
Underground
Below the surface of the ground.
Chennai's metro runs underground in some places.
Underline
To draw a line under words.
Underline the main verb in each sentence.
Remember: Under- can mean 'below' (underground) or 'not enough' (underpaid). Not every 'under' is this prefix: understand does not mean 'stand below'.