Oxford American defines it to throw carelessly or casually, to give up, to resign, to touch playfully under the chin, to throw away. Both noun and verb, ‘chuck’ is also slang for food.
Directly beneath chuck are chuckhole, chuckle, chug, chukka and chukker. In case you have not cracked a dictionary lately, chukka is a boot and chukker is not a bird, it is a period of play in polo.