Synonyms of the word

conceptive

• adj. relating to conception (in all senses).

fertile

• adj. (of land etc) capable of growing abundant crops; productive.
• adj. (biology) capable of reproducing; fecund, fruitful.
• adj. (biology) capable of developing past the egg stage.
• adj. (of an imagination etc) productive or prolific.

impregnable

• adj. (of a fortress, wall, etc., also used figuratively) Too strong to be penetrated.
• adj. Capable of being impregnated.