Straightforward adjective… but no, also an adverb (to stand tall – 07.096). Straightforward meaning about height… but no, a whole family of meanings related to speed and to adeptness. Probably just the height meaning for The Hobbit, though.

• 1.007 He had a tall pointed blue hat,
• 1.063 and made tall piles of all the things.
• 3.008 and tall;
• 3.021 a tall young fellow,
• 4.004 over those great tall mountains
• 5.026 Is taller than trees,
• 5.146 into a narrow valley between tall mountains;
• 6.045 with tall fronds rising right above the hobbit’s head;
• 6.052 Fili and Kili were at the top of a tall larch
• 6.052 Dwalin and Balin had swarmed up a tall slender fir
• 6.052 Gandalf, who was a good deal taller than the others,
• 6.064 stuck up in a tall tree
• 7.014 and the tall elms.
• 7.029 After a while they came to a belt of tall
• 7.036 and towering tall above Gandalf.
• 7.094 and on the table were two tall red beeswax candles.
• 7.096 with the pillars of the house standing tall behind them,
• 7.146 and wishing he was beside the wizard on his tall horse.
• 8.040 is to choose the tallest tree
• 8.044 though it was tall
• 8.102 between two tall trees
• 8.131 that grew tall
• 10.028 surrounded by the tall piles
• 11.001 and tall before them.
• 11.006 tall and steep above the stream;
• 13.048 In front there rose a tall arch,
• 14.028 a tall figure stepped from the shadows.
• 15.036 Under the Mountain dark and tall
• 15.042 and tall.
• 15.046 A tall man stood forward,