Meaning : Not suitable to your tastes or needs.
Example :
The uncongenial roommates were always fighting.
The task was uncongenial to one sensitive to rebuffs.
Synonyms : incompatible
Suitable to your needs.
A congenial atmosphere to work in.Meaning : Very unfavorable to life or growth.
Example :
A hostile climate.
An uncongenial atmosphere.
An uncongenial soil.
The unfriendly environment at high altitudes.
Synonyms : hostile, unfriendly
Meaning : Used of plant stock or scions. Incapable of being grafted.