Definition 1 of 2
Literally "mother's vagina".
Often used as an exclamation "ma ki chooth! I'll never be able to finish all this work". Can be substituted with "ma ki aankh" in presence of people with delicate sensibilities.
Also used as an expletive when associated with someone "Teri ma ki chooth", which means "your mother's vagina", implying that the person using the phrase will do unspecified acts to his antagonist's mother's vagina.
Added 2011-07-12 by Gyaani