adj.not readily apparent

"the answer was at first unapparent"

Unapparent virus infection and host fitness in three weedy grass species.
Clinically unapparent infantile thiamin deficiency in Vientiane, Laos.
Discovery of unapparent association rules based on extracted probability
Unapparent microsporidial infection among immunocompetent humans in the Czech Republic
Unapparent foot and mouth disease infection (sub-clinical infections and carriers): implications for control.
On the cryptic side of life: being unapparent to enemies and the consequences for foraging and growth of caterpillars
On the cryptic side of life: being unapparent to enemies and the consequences for foraging and growth of caterpillars
Virus infections in wild plant populations are both frequent and often unapparent
Evidence of occult HCV genotypes in haemophilic individuals with unapparent HCV mixed infections.
Optical methodology for detecting histologically unapparent nanoscale consequences of genetic alterations in biological cells