keep vs observe

keep

verb
  • To observe; to adhere to; to fulfill; to not swerve from or violate. 

  • To supply with necessities and financially support (a person). 

  • To refrain from freely disclosing (a secret). 

  • To continue in (a course or mode of action); to not intermit or fall from; to uphold or maintain. 

  • To remain edible or otherwise usable. 

  • To remain in a state. 

  • To raise; to care for. 

  • To have habitually in stock for sale. 

  • To act as wicket-keeper. 

  • To enter (accounts, records, etc.) in a book. 

  • To maintain the condition of; to preserve in a certain state. 

  • To restrain. 

  • To maintain (an establishment or institution); to conduct; to manage. 

  • To watch over, look after, guard, protect. 

  • To maintain possession of. 

  • To record transactions, accounts, or events in. 

  • To remain faithful to a given promise or word. 

  • To continue. 

noun
  • The state of being kept; hence, the resulting condition; case. 

  • A cap for holding something, such as a journal box, in place. 

  • The food or money required to keep someone alive and healthy; one's support, maintenance. 

  • The main tower of a castle or fortress, located within the castle walls. 

observe

verb
  • To notice or view, especially carefully or with attention to detail. 

  • To take note of and celebrate (a holiday or similar occurrence); to follow (a type of time or calendar reckoning). 

  • To comment on something; to make an observation. 

  • To follow or obey the custom, practice, or rules (especially of a religion). 

How often have the words keep and observe occurred in a corpus of books? (source: Google Ngram Viewer )