This is the 10822nd most frequent French word.
observerez
"Observerez" means "will observe."
'Observerez' in this question is used to mean following or adhering to rules or guidelines.
Observerez-vous les règles de cette compétition ?
Will you observe the rules of this competition?
'Observerez' in this instance refers to perceiving or noticing a change or result as an outcome of an action.
Si vous suivez mes conseils, vous observerez une amélioration dans vos performances.
If you follow my advice, you will observe an improvement in your performances.
'Observerez' is used here to describe the action of noticing or watching attentively something in the future.