variant of 疏[shu1]
Phonosemantic compound. 疋 represents the sound and 㐬 represents the meaning. Based on the original meaning "unblock, get things flowing". The meaning later shifted to "open up", "sparse", "wide apart", and "neglect".
《說文》：“疏，通也。从，从疋，疋亦聲。”
unblock, get things flowing