What does the cryptic crossword clue "Side pedal's got loose making one unhappy (10)" mean?

The definition is "unhappy". The wordplay uses an anagram. anagram of SIDE + PEDAL'S = DISPLEASED; definition: "unhappy" The answer is DISPLEASED.

Side pedal's got loose making one unhappy (10)

Daily Mail Cryptic #17393 | 13 Across | 2024-07-03 flower