lén

lén
adv
  1. stealthily; covertly; secretly

verb
  1. (archaic) Synonym of lẻn (“to act secretly”)

lên

lên
verb
  1. to go up, come up, rise
  2. to be or reach a certain age
  3. to get on (a vehicle)
  4. to go to (a more developed area)
  5. (of a machine) to be activated

adv
  1. upwards