Definition: An injunction to put something out of one's hopes, concern, etc, esp because it is impossible.
Variation: Oh, it was nothing important -- forget it."
Also sign synonyms found in NEVER-MIND.
Gloss: IX-me CAN GET-UP++ (TEND) MOSTLY /\conj-UNDERSTAND/\ WINTER/\ [neg] DISMISS/NO-THANK [gesture].
English equivalent: I can get up there most of the time, but in winter, forget it.
The gloss UNDERSTAND is a conjunction, not the same meaning as the verb "understand". It's somehow equivalent to HOWEVER, BUT, and alike.