1. used of plant stock or scions
incapable of being grafted

2. not suitable to your tastes or needs

e.g. the uncongenial roommates were always fighting
the task was uncongenial to one sensitive to rebuffs

Synonym: incompatible

3. very unfavorable to life or growth

e.g. a hostile climate
an uncongenial atmosphere
an uncongenial soil
the unfriendly environment at high altitudes

Synonym: hostileunfriendly