filiform

/F IH1 L AH0 F AO0 R M/
adjective
  1. 1

    Shaped like or resembling a thread or filament; filamentous.

  2. 2

    Having all component parts or segments cylindrical and more or less uniform in size.

    โ€œTiger beetles have filiform antennae.โ€

Source: https://en.wiktionary.org/wiki/filiform