Definition: recognize the full worth of; to recognize how good someone or something is and to value him, her, or it.
Two variations shown in the video, depending on the contexts. The former is a regular verb or noun (depending on the order of an ASL sentence). The latter sign has a prefix sign which can mean "really appreciate", "deeply appreciate" or such.
Captured an old ASL in the film "The Preservation of American Sign Language" filmed in 1913 by the signer George Veditz. The ASL word signed by George Veditz in 1913 is interesting.
Related signs THANK-YOU