1. 不合适的；不得体的
If you say that some-one's behaviour is unseemly, you disapprove of it because it is not polite or not suitable for a particular situation or occasion.
1. not in keeping with accepted standards of what is right or proper in polite society
e.g. was buried with indecent haste
indecorous behavior
language unbecoming to a lady
unseemly to use profanity
moved to curb their untoward ribaldry