- Morally or legally constraining; binding. (adjective)
- Imposing or recording an obligation: a bill obligatory. (adjective)
- Of the nature of an obligation; compulsory: Attendance is obligatory. Mathematics is an obligatory course. (adjective)
- Biology Obligate. (adjective)
- Required to be done, obtained, possessed, etc (adjective)
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
- Of the nature of or constituting an obligation (adjective)
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