The avyayībhāva

avyayībhāva literally means “uninflected state.” Usually, the first word of an avyayībhāva is an uninflected word and the second word extends or clarifies the first one:

• यथा + शक्ति → यथाशक्ति
  yathā + śakti → yathāśakti
  according to + power → according to one's power
  

• प्रति + पदम् → प्रतिपदम्
  prati + padam → pratipadam
  against, regarding → at every word, for each word
  

• यावत् + जीवम् → यावज्जीवम्
  yāvat + jīvam → yāvajjīvam
  as much as + life → throughout one's life