Meaning of the Sanskrit Word: vastutah

  vastutah—in fact    Adi 16.97, Madhya 1.225, Antya 4.198
  vastutah—factually    Adi 7.123, Madhya 22.29
  vastutah—the original substance.    SB 5.18.5
  vastutah—with the proper ingredients    SB 5.19.26
  vastutah—at the ultimate issue    SB 6.8.31
  vastutah—in fact.    SB 7.13.5
  vastutah—and paraphernalia    SB 8.23.16

Can't find any compound Sanskrit words containing vastutah.